CA3043728A1 - Apparatus and method for extending shelf life and prevention of discoloration of meat - Google Patents

Abstract

The current invention covers an improved meat-packaging procedure and machine for packaging meat cuts for long-term storage at temperatures of between 28° and 32° F. The process includes sealing meat cuts within a master bag containing oxygen scavenger materials capable of reducing the residual oxygen content of the atmosphere within the bag to 0 ppm within 24 hours of sealing. Gas is injected into the master bag to form a nitrogen-rich storage environment of at least 50% nitrogen. A small amount of carbon monoxide gas (0.1% to 5%) is preferred for the storage environment, as this helps to preserve the red coloration of meat under long-term storage conditions. The over-wrap of the meat trays can be perforated so that gas exchange occurs within the master bag between the interior and exterior of the meat tray to absorb the residual oxygen inside the meat trays. For meat trays containing meat with poor color stability, oxygen scavengers are preferably placed within the meat trays. For cuts with good color stability, the oxygen scavengers may be placed outside the meat trays. Meat can be stored by this system for up to 15 weeks and up to nine days of retail display life.

Description

US 2006/0228449 Al Oct.
12, 2006 APPARATUS AND METHOD FOR EXTENDING different from those needed to extend shelf-life of fresh SHELF-LIFE AND PREVENTION OF chilled meat for periods of up to fifteen weeks. Deterioration DISCOLORATION OF MEAT of chilled meats primarily takes place at the cut or uncut muscle surface. In long term storage at a centralized pack-RELATED APPLICATION DATA aging and storage operation, primal cuts are placed in an atmosphere saturated with carbon dioxide (CO2) (100%) [0001] This application is a continuation-in-part of U.S. which contains very low residual oxygen (02), and these application Ser. No. 10/192,916 and U.S. application Ser. primal cuts stored at ¨1.5+/-0.5 C.
No. 10/434,010, which is also a continuation-in-part of Ser.
[0007] At the end of required storage, meat is removed and No. 10/192,916, and claims the benefit of U.S. Provisional fabricated into retail or food service cuts. New fresh surfaces Application 60/303,985, U.S. Provisional Application are created in the process, revitalizing the appearance of the 60/379,668, and U.S. Provisional Application 60/729,077.
meat cuts; and when the new surfaces of the meat cuts are Applicant further incorporates these previous filings by prepared for retail display the normal expectation is a further reference.
four days of shelf-life. Depending on the variability of the meat species, the shelf-life is usually limited by develop-TECHNICAL FIELD OF THE INVENTION
ment of undesirable organoleptic changes, where defects in

[0002] The present invention relates to a packaging sys- color are usually independent of the microbial presence. The tern, method, and apparatus of increasing the shelf-life of latter has a lactic acid bacterial population, which maximizes retail-ready meat cuts and preventing discoloration of meat under storage conditions at levels about 108 cfu/cm2 well products. before the shelf-life expiration.
[0008] However, with centralized distribution of retail BACKGROUND OF THE INVENTION ready fresh meat, circumstances and storage requirements are different. The wholesale storage period following initial

[0003] Meat production and packaging is well known in packaging of the retail cuts is in the range of 20-30 days and the industry. Traditionally, once a primal cut of meat has - prepared products must withstand the rigor of retail display been made, it is placed in a package containing ambient air for up to two days thereafter without further manipulation of and the lidding material is fed from a roll and over the tray the contents of the package. Retail packages are simply covering the meat cut. The tray edges are typically sealed to moved from their storage container (usually a unit or over-form the finished product. However, since the air allows the meat to become discolored due to the onset of metmyoglo- wrap containing a modified atmosphere) to retail display where desirable meat color develops upon exposure to air.
bin, the meat normally undergoes vacuum skin packaging in The present commercial centralized meat operations only order to maintain freshness and reduce spoilage of the meat provide one to two weeks of shelf-life. Whereas, in North cut.
America, total shelf-life of several weeks (i.e. at least greater

[0004] The conventional vacuum packaging process nor- than four weeks) is desired because of distant markets and mally does not allow the meat cut to exhibit a deep red intent of North American meat industry to export to distant pigment desired by retailers and consumers. Subsequently, countries. Hence, the goal is to extend the shelf-life of once these vacuum-packed meat cuts reach the supermarkets retail-ready meat cuts.
or meat distribution centers, the primal cuts are cut into [0009] A number of approaches have been taken to extend smaller cuts. These smaller cuts are then repackaged or the shelf-life of meat. The basic approach is to package meat displayed in a case for sale. In a very short time, the meat cuts with an inert gas atmosphere after the meat has been cuts lose the desired red color and start to brown or other- shipped from a processing facility to a retail outlet. There-wise become discolored, losing its aesthetic fresh, healthy alter, when the retail outlet receives the packaged meat, the appearance and often not sold as a result. inert gas within the package is replaced with an oxygen-

[0005] Specifically, meat cuts lose their healthy color due containing atmosphere.
to metmyoglobin (aka browning of meat). Metmyoglobin [0010] One example of such a packaging system is occurs because of oxidation of deoxymyoglobin, and this depicted in U.S.
Pat. No. 4,055,672 issued in 1977. The '672 chemical reaction of the meat is irreversible. Under a patent provides for a system in which a meat product is reduced oxygen condition, the rate of the metmyoglobin is packaged with one of the package walls formed from a gas high. Transient discoloration can occur in a reduced oxygen impermeable material and another package wall formed as environment, because meat muscle possesses a limited enzy- an inner gas permeable layer and an outer gas impermeable matic activity known as metmyoglobin reducing activity layer. The meat cut is initially packaged in an inert gas (MRA) which converts metmyoglobin back to deoxymet- atmosphere which is maintained within the package by the myogjobin However, this process, which can decrease and package walls including the outer gas impermeable wall possibly reverse discoloration, takes several days and is layer. If the outer gas impermeable layer is removed, this detrimental to centralized meat operations. Furthermore, the enables the oxygen-containing ambient air to flow into the MRA is extremely limited and once consumed by the meat package through the gas permeable layer. However. the '672 cannot be rejuvenated, patent allows the meat to deteriorate after the impermeable

[0006] Despite the inherent drawback, centralized pack- layer has been removed, unless an additional impermeable aging of retail meat cuts is gaining in popularity in the food layer is added. Nevertheless, placing a gas impermeable film industry due to its economies and the potential to maintain layer over a gas permeable film layer is expensive to produce quality, enhance safety, and extend the shelf-life of fresh and difficult to seal to a container.
meat. However, the general requirements to optimize shelf- [0011] Another example of packaging containing an inert life of centrally prepared retail-ready meat cuts are slightly gas atmosphere is depicted in U.S. Pat. No. 6,302,324 issued US 2006/0228449 Al Oct.
12, 2006 in 2001. The '324 patent provides for packaging a food netic south sides.
here, the negative magnetic north sides of product in a receptacle containing an inert gas atmosphere the magnetic strips or pads are arranged to impinge on the and sealing a film to the receptacle. The receptacle includes fresh food products stored in a low-temperature environ-a sealing flange and a tab portion extending from the sealing ment.
However, the '105 and '215 patents achieve a wetter flange to which the film is sealed. The tab and the film are condition thereby establishing a longer shelf-life condition removed from the package to form an opening between the for foods which are stored in a combined environment to film and the receptacle when the food product is ready to be include a north magnetic field and a selected low tempera-displayed to consumers. An atmosphere exchange operation turc.
is carried out through the opening, by inserting a nozzle .-L0015] Another example of a shelf-life extender for food through the opening and introducing an oxygen-containing use is depicted in U.S. Pat. No. 5,985,303 issued to Okada gas into the receptacle cavity through the opening. The inert in 1999. The '303 shelf-life extender incorporates an isothio-gas atmosphere initially contained within the receptacle is cyanic acid compound being supported on a matrix, where exhausted through the opening and the nozzle is withdrawn the compound is packaged in synthetic resin film or non-from the opening. The opening is closed by sealing the film woven fabric. However, the '303 patent concentrates on to the receptacle. The '324 patent allows an inert gas acidic chemical compounds and gelling agents as opposed to atmosphere within the interior of the package to be easily integrating a zero oxygen packaging system as described by and quickly replaced with an oxygen-containing atmo-the present invention.
sphere.
[0016] U.S. Pat. No. 6,153,241 describes another method [0012] U.S. Pat. No. 6,408,598 also provides for a modi-and a package for extending the shelf-life of a food. Spe-fied atmosphere packaging process including the steps of cifically, the method of achieving an extended shelf life for providing a tray, providing an upper film which includes a a food includes enclosing the food in a discrete container sealant layer which is sealable to the tray, orienting the film .
having a first and a second container position, treating the to an orientation ratio of from about 6.0:1 to about 16.0:1 food in the discrete container with heat in a treatment positioning, a high profile product on the tray, extending the chamber while the container maintains the first container upper film above the tray and product, drawing the upper position and raising the container to the second container film into a concavity by differential pressure, maintaining position under which the container is distributed, sold or the concave shape of the upper film while heating the film, used. However, contrary to the present invention, the '241 removing gases from the space between the upper film and patent describes a method of heat treating a pumpable food the tray and product, introducing a desirable gas into the i carried out n a treatment chamber.
space, releasing the upper film such that it shrinks toward the product and the tray while the desirable gas is retained [0017] U.S. Pat.
No. 6,183,790 to Delducca et al and U.S.
within the space preventing close contact of the film with the Pat. No.
6,666,988 to Carr et al utilize an external oxygen lowermost portions of the product and sealing the upper film accelerator to activate an oxygen scavenger to reduce the to the flange of the tray, wherein at least the step of heating oxygen concentration to 500 parts-per-million (ppm) within the film shrinks the film, thereby tensioning it onto and 90 minutes.
However, even at these low oxygen levels across the underlying product. metmyoglobin formation remains very high (See FIG. 1).
This stems from the fact that transient discoloration occurs [0013] Another patent for extending the shelf-life of meat because of limited metmyoglobin reducing activity (MRA) has been depicted in the process for pre-packing fresh meat with the meat muscle, and these patents fail to address this seen in U.S. Pat. No. 4,683,139. The '139 patent describes process.
a process where the meat is treated with an aqueous solution containing three active components, namely phosphate corn- [0018] U.S. Pat.
No. 6,269,946 to Colombo includes use pounds, a reducing agent and a sequestering agent; and then of a meat tray over-wrapped with a gas permeable film. This packaging the meat in a controlled gaseous atmosphere patent uses metal chloride inside a meat tray to combine with containing from about 20% to 80% carbon dioxide and from water and acid to produce chlorine dioxide to help preserve about 2% to 30% oxygen, with the balance being nitrogen. meat cuts packaged therein. The disclosed invention also Specifically, the process includes (1) placing at least one claims oxygen absorbers packaged within a barrier bag, but pork chop on each of a plurality of semi-rigid trays; (2) the patent fails to discuss the importance and advantages of placing a gaseous mixture over and around the chops on sealing oxygen scavengers inside the meat tray or the need each of the trays; (3) sealing the trays with a gas permeable to quickly obtain a zero-oxygen gas environment for long-film; (4) placing a plurality of the trays on a thermoformed term cold storage of meat cuts both within the meat tray and tray; and (5) covering and sealing the thermoformed tray the barrier (e.g.
master) bag. The patent only provides for with a gas impermeable film. However, the '130 patent very low oxygen environment of about less than 0.05%
concentrates on the centralized pre-packing of fresh meats at volume of oxygen and does not attain zero oxygen levels.
the meat packing plant prior to shipment to the point of Further, the meat tray adds a receptacle for injecting carbon storage or retail sale. Further, the '139 patent fails to include dioxide into the meat tray, and does not recommend a 100% nitrogen gas filling a master bag before the placement nitrogen-rich gas environment for storage, instead favoring of the tray. carbon dioxide. Carbon dioxide is not preferred for several [0014] Other examples of inventions desiring to extend the reasons.
shelf-life of food products are U.S. Pat. Nos. 5,527,105 and [0019] Other U.S. Patents and publications (U.S. Pat. Nos.
5,705,215 issued to Riach, Jr. The '105 and '215 patents 6.230,883, 6,447,826, 6,586,651, 6,592,919) recommend provide for a magnetic method for extending the shelf-life of using an atmospheric mixture containing carbon dioxide or food products wherein magnetic strips, matting formed from discuss methods to create an atmosphere of carbon dioxide.
the strips and pads having magnetic north sides and mag- However, in these inventions, although carbon dioxide has US 2006/0228449 Al Oct.
12,2006 anti-microbial activity, solubility increases at low tempera- However, beef with poor stability is highly susceptible to ture and it is absorbed into the meat cuts, and after long metmyoglobin formation even at very low 02 concentrations storage the meat starts to discolor from the inside out. For and subzero temperatures, and these cuts require a zero-this reason, carbon dioxide is only successful for long-term storage environment for long-term storage.
storage of primal or sub-primal meat cuts or uncut carcasses.
[0024] If the enzymes causing MRA are retained in the However, for retail ready cuts, use of carbon dioxide is meat, longer shelf life of meat cuts is possible. To accom-detrimental to the meat color if long-shelf life of case-meat plish this, the oxygen concentration in the master-bags used is desired. Solublization of carbon dioxide into the meat to ship meat from a central meat operation containing groups prevents and/or delays meat cuts from re-blooming when of meat trays must be zero. Under zero-oxygen concentra-master bags containing retail meat cuts are opened and the tion. meat color will go to the de-ox state and will come back meat exposed to air.
to ox-state with the master-bags containing trays are opened [0020] In other systems utilizing activated oxygen scav- and exposed to atmosphere. By doing this procedure, the engers as mentioned by Delducca et al and Carr et al, the enzymes causing MRA are retained and the meat does not go presence of carbon dioxide hinders the rate of oxygen through a transient discoloration and long shelf-lives can be absorption by oxygen scavengers due to formation of car- attained. The present invention has been developed to alle-boxylic acid (carbon dioxide reacting with residual oxygen), viate the above-identified drawbacks and provide further hence the lowest oxygen concentrations obtained with these benefits to the meat distribution centers, supermarkets and systems is 500 ppm within 90 minutes, and other issues the consumer.
regarding transient meat discoloration remain unsolved. [0025] The goal of the invention is to provide meat packers with an integrated packaging system that incorpo-[0021] Present commercial centralized meat operations rates oxygen scavengers along with automatic formation of employ master packaging in which three or more trays, each master-bags to fit the size of meat-trays, family size or containing retail-ready meat cuts, are placed in a gas-multi-individual trays, and gas-flushing and sealing. The impermeable master bag. However, residual oxygen may be packaging system reduces the oxygen concentration to 0 present inside the packages due to the entrapment of oxygen during controlled atmosphere packaging (CAP). Specifi- ppm within a short period of time after pack closure. The invention uses modified horizontal, form, fill, and seal cally, the residual oxygen may be present due to any one of the following factors: (1) insufficient oxygen evacuation; (2) equipment with different packaging size options. The pack-insufficient flushing times during CAP-machine operations; aging equipment is intended to operate exclusively in meat (3) use of an improper ratio of meat-mass to package operations utilizing oxygen scavengers, but may be adapted atmosphere resulting in dead space in the master bag; (4) for operations with long-term storage in a carbon dioxide oxygen entrapment in the retail trays themselves, in absor-environment.
bent pads or under the meat cut; (5) oxygen ingress through SUMMARY OF THE INVENTION
seams of a film used to over-wrap a master pack; (6) film defects; or (7) oxygen release from meat muscle. Since some [0026] The present invention in its several disclosed of these factors are inevitable in commercial meat packaging embodiments alleviates the drawbacks described above with operations, the plain use of master packaging has found respect to traditional meat packaging and incorporates sev-limited application in commercial centralized meat opera- eral additionally beneficial features. The process of packag-tions. Therefore, a system is needed to reduce the oxygen ing meat, namely retail-ready meat, is known in the prior art.
concentration in a relatively short period of time in order to Disclosed herein is a packaging system and method of same restore the metmyoglobin reducing activity, developed to prevent meat discoloration of prepared fresh [0022] Previously issued patents and prior art procedures meat cuts, such as beef, pork, lamb, and chicken. Specifi-reduce the oxygen concentration to at best 500 ppm within cally, different packaging configurations use self-activated oxygen scavengers and structures to extend the shelf life of 90 minutes. These processes can result in some extension of shelf life of case-ready meat cuts for retail sale, however fresh meat cuts by attaining a zero oxygen-packaged envi-ronment.
these oxygen concentrations still lead to transient meat disclosure. For meat-packaging implementing national and [0027] When fresh meat is exposed to oxygen, two effects international centralized meat packing operations, extremely normally occur. First, bacteria begins to grow and subse-long shelf life in the range of 8-10 weeks is desired. This quently the fresh meat color disappears. By eliminating long of a shelf-life can only be obtained if the transient meat exposing the meat to oxygen, the chances of reducing discoloration can be avoided. Consequently, premature tern- bacteria and extending the fresh meat color improve dra-poraxy discoloration limits the advantages of centrally pack- matically. As a result, the present invention effectively aged retail ready meat cuts using current oxygen depleted removes oxygen very rapidly from a sealed package thereby master packaging methods because a zero-oxygen storage increasing the shelf-life of the meat up to 12 weeks or more environment is not attained, for different meat types.
[0023] Discoloration is also dependent on the specific [0028] The disclosed packaging system extends the shelf-muscle packaged since tissue vary in capacity to withstand life of centrally prepared retail-ready meat cuts by restoring low oxygen concentrations (<500 ppm). Centrally prepared metmyoglobin reducing activity of the meat-muscle through beefsteaks and ground beef packaged under controlled atmo- zero oxygen packaging. This achieves extremely long shelf-spheres are shown to be susceptible to very low oxygen life for storage of retail-ready meat cuts. A retail-ready meat concentrations. Beef muscle with high color stability are cut is placed in a tray having an activated oxygen scavenger least susceptible to metmyoglobin formation if the atmo- based upon an iron chemical system and an absorbent pad.
sphere is maintained at <600 ppm 02 at temperatures <0 C. Several of these trays are placed in a master bag that is filled US 2006/0228449 Al Oct.
12, 2006 with a high nitrogen gas mixture and sealed. Several differ- bags and meat packages to between 0.6 and 2.0 hours. The ent combinations of placing scavengers (based upon iron master bags are formed around the meat trays and the chemical systems) and optimization of the oxygen scaveng- ambient air is flushed from the bag. The bag is then injected ing capacity in each tray are achieved, with the desired gas mixture environment that is preferably 100% nitrogen or nitrogen rich (>50%) with the balance a [0029] The tray or the master bag containing optimum mixture of other gases, preferably carbon monoxide and oxygen scavenging capacity results in 0.6-2.0 hour half-life carbon dioxide. Some small quantity of carbon monoxide for oxygen in the master bag (depending upon the initial (>0.1%) is preferred. The master bags can then be stored for oxygen concentration and meat-type) and is the one desired several weeks at freezing or below freezing temperatures for centrally prepared retail-ready meat cuts. Such a pack- (28 -32 F.) until needed for placing into a retail display for aging system under 100% nitrogen atmosphere resulted in at several days before meat discoloration occurs.
least a ten week storage life for centrally prepared meat cuts, such as beef tender loin steaks, with a subsequent display DESCRIPTION OF THE DRAWINGS
life of at least three days.
[0035] lhe objects and features of the invention will [0030] Thus, the use of an activated oxygen scavenger and become more readily understood from the following detailed an absorbent pad inside a master bag having 100% nitrogen description and appended claims when read in conjunction introduced therein provides a significant increase in profits with the accompanying drawings in which like numerals by reducing spoilage. By reducing the partial pressure of oxygen to zero ppm in the master bags, the growth of the represent like elements and in which:
aerobic spoilage and pathogenic microorganisms is inhibited [0036] FIG. 1 is a x-y graph depicting the influence of thereby extending the storage and display life of retail-ready oxygen partial pressure on three chemical states of myoglo-fresh meat packages. Additionally, this process preserves the bin;
vivid, bright cherry red color of red meats, whereby longer shelf life and better looking meat products translate into [0037] FIG. 1A
is a table displaying the half-life of higher sales and higher profits. Moreover, the master pack- oxygen in bags containing scavengers based upon enzymes age will reduce purge due to temperature changes and will and iron chemical systems in an air or nitrogen atmosphere actually enhance the natural aging process producing more as described in Example 1;
flavorful and tender cuts of fresh meat.
[0038] FIG. 18 is a table showing constants of first order [0031] Another advantage of the present invention is that kinetics equation for various scavengers;
a retailer is capable of unpackaging a days' supply of fresh [0039] FIG. 2A is a table describing treatments for beef meat cuts at a time. The master package is protected from steaks and pork chops as described in Example 2;
oxygen exposure until the seal is released and the individual packages are placed in the retail case. In essence, the shelf [0040] FIG.
2B is a table depicting oxygen concentration life clock does not begin ticking until the fresh meat is in master packs containing beef and pork stored at 2 C. in placed in the retail case. For central packaging operations, 100% nitrogen atmosphere over the course of seven days as by utilizing the master packages, the shrinking of meat cuts described in Example 2;
due to handling, transportation and temperature fluctuations is greatly reduced to virtually zero shrinkage. [0041] FIG. 2C is a table displaying mean color, surface discoloration and retail appearance scores and standard [0032] The main advantage of the invention is the zero- errors for pork chops and beef steaks after various treat-oxygen system gas environment in the master bag stops the ments;
tbnnation of metmyoglobin, the agent that causes fresh meat to become discolored. By stopping metniyoglobins forma- [0042] FIG. 2D is a table depicting mean values of the tion, the metmyoglobin reducing activity (MRA) of the meat chemical states of myoglobin (% met-, % deoxy-, and %
muscle is retained. Because the oxygen concentration in the oxy-myoglobin) and standard errors of difference for pork master bag is zero ppm, metmyoglobin cannot form and the chops and beef steaks after various treatments:
discoloration process never occurs. Further, under the zero-[0043] FIG. 2E is an x-y graph depicting a discoloration oxygen system, only lactic acid and other slow growing anaerobic bacteria will grow; and the growth of faster score given to bags undergoing various treatments as growing aerobic bacteria causing rapid spoilage is restricted, described in Example 2;
[0044] FIG. 2F is an x-y graph depicting a retail appear-[0033] Shelf-life in the retail case is increased by one to seven additional days, depending upon the type of meat cut. ance score given to bags undergoing various treatments as The present packaging system preserves the enzymatic described in Example 2;
activities of meat-muscle that maintains the bright cherry red [0045] FIG.
2G is an x-y graph showing different treat-color of each meat cut, the retail display life of the meat is ments given a discoloration score during retail display times extended dramatically. The addition of carbon monoxide as as described in Example 2;
part of the gas mixture environment also helps preserve the reddish color of the meat as a layer of carbon monoxymyo- [0046] FIG. 211 is an x-y graph illustrating different globin is formed on the meat surface, treatments given a retail appearance score during retail display times as described in Example 2;
[0034] The apparatus used in the invention will automati-cally package meat trays into a single master bag containing [0047] FIG. 21 is an x-y graph showing different treat-oxygen scavengers with appropriate oxygen absorption ments having a certain percentages of metmyoglobin during capacity to reduce the half-life of oxygen inside the master retail display times as described in Example 2;

US 2006/0228449 Al Oct.
12, 2006 [0048] FIG. 3A is an x-y graph depicting a control and [0066] FIG. 5J is an x-y graph showing color scores of two experimental types given a discoloration score within meat, namely lamb chops in foam trays, based on time of storage intervals as described in Example 3; retail display as described in Example 5;
[0049] FIG. 38 is an x-y graph illustrating the control and [0067] FIG. 6A
is an x-y graph showing color score of two experimental types given a retail appearance score meat, namely pork chops, based on time of retail display within storage intervals as described in Example 3; over a period of time as described in Example 6;
[0050] FIG. 3C is an x-y graph illustrating the control and [0068] FIG. 6B
is an x-y graph showing discoloration of two experimental types having a percentage of metmyoglo- meat, namely pork chops, based on time of retail display as bin taken during storage intervals as described in Example described in Example 6:
3; [0069] FIG. 6C is an x-y graph depicting scores of retail [0051] FIG. 4A is an x-y graph showing different weeks appearance of meat, namely pork chops based on time of receiving color scores during retail display times as retail display as described in Example 6;
described in Example 4;
[0070] FIG. 6D is an x-y graph showing scores of off-odor [0052] FIG. 40 is an x-y graph showing different weeks intensity of meat, namely pork chops, based on the time of receiving discoloration scores during retail display times as retail display as described in Example 6;
described in Example 4;
[0071] FIG. 6E is an x-y graph detailing odor acceptabil-[0053] FIG. 4C is an x-y graph showing different weeks ity of meat, namely pork chops, based on the amount of time receiving retail appearance scores during retail display times the chops are displayed as described in Example 6;
as described in Example 4;
[0072] FIG. 6F is an x-y graph depicting microbial plate [0054] FIG. 4D is an x-y graph showing different weeks count for meats, namely pork chops, based on time the chops receiving off odor intensity scores during a course of days of are displayed as described in Example 6;
retail display as described in Example 4;
[0073] FIG. 7 is a schematic flow chart showing the [0055] FIG. 4E is an x-y graph showing different weeks method of the process used for packaging meat under the receiving odor acceptability scores during a course of days invention;
of retail display as described in Example 4;
[0074] FIG. 8 is an embodiment of the arrangement of the [0056] FIG. 4F is an x-y graph depicting different weeks elements of a meat tray;
showing a microbial count during a course of days of retail display as described in Example 4; [0075] FIG. 9 is another embodiment of the arrangement of the elements of a meat tray;
[0057] FIG. 5A is an x-y graph depicting a microbial plate [0076] FIG. 10 is an embodiment of the arrangement of count for meats, namely lamb chops stored on foam trays meat trays inside a master bag;
over a period of time as described in Example 5;
[0058] FIG. 5B is an x-y graph illustrating microbial plate [0077] FIG. 11 is an embodiment of a master bag con-count for meats, namely lamb chops stored on plastic trays taming a large primal or sub-primal meat cut;
over a period of time as described in Example 5; [0078] FIG. 12 is another embodiment of the arrangement of meat trays and oxygen scavengers inside a master bag;
[0059] FIG. SC-I to 5C-I1 is an x-y graph detailing odor and acceptability of meat, namely lamb chops, based on the amount of time the chops are displayed as described in [0079] FIG. 13 is a schematic drawing of an apparatus to Example 5; package meat according to the disclosed method and pro-[0060] FIG. SD-I and 5D-I1 is an x-y graph showing cess.
scores of off-odor intensity based on the amount of time the DETAILED DESCRIPTION OF THE
chops are displayed as described in Example 5;
PREFERRED EMBODIMENTS
[0061] FIG. 5E is an x-y graph depicting scores of retail room] As required, detailed embodiments of the present appearance of meat, namely lamb chops based on time of [
retail display in plastic trays as described in Example 5; invention are disclosed herein; however, it is to be under-stood that the disclosed embodiment(s) are merely exem-[0062] FIG. 5F is an x-y graph depicting scores of retail plary of the invention that may be embodied in various and appearance of meat, namely lamb chops based on time of alternative forms.
Specific structural and functional details retail display in foam trays as described in Example 5; disclosed herein are not to be interpreted as limiting, but [0063] FIG. 5G is an x-y graph illustrating surface dis- merely as a basis for the claims and as a representative basis coloration of meat, namely lamb chops in plastic trays based for teaching one skilled in the art to variously employ the on time of retail display as described in Example 5; present invention.
Further, the particular materials and amounts thereof, as well as other conditions and details, [0064] FIG. 5H is an x-y graph detailing surface discol- recited in these examples should not be used to unduly limit oration of meat, namely lamb chops, in foam trays based on this invention.
time of retail display as described in Example 5;
[0081] The present invention in its several disclosed [0065] FIG. 51 is an x-y graph showing color scores of embodiments alleviates the drawbacks described above with meat, namely lamb chops in plastic trays, based on time of respect to traditional meat packaging and incorporates sev-retail display as described in Example 5; eral additionally beneficial features. The process of packag-=
US 2006/0228449 Al Oct.
12, 2006 ing meat, namely retail-ready meat, is known in the prior art. tray overwrap consisted of additional ambient atmosphere Disclosed herein is a packaging system and method of the flow with multiple holes, each having a diameter of less than same developed to prevent meat discoloration of prepared 5 mm, punched through the overwrap or a single needle hole fresh meat cuts, such as beef, pork, lamb, and chicken. with a diameter of less than 5 mm.
Specifically, different packaging configurations of compo-Master Bag Characteristic nents of the system use self-activated oxygen scavengers and structures to extend the shelf life of fresh meat cuts. A [0086] The meat trays containing different meat cuts in number of different options have been tested. different numbers (one to six retail trays) are placed in a Oxygen Scavengers master bag possessing good seal strength. The master bag possesses good seal strength with either a foil lining or an [0082] Oxygen scavengers based on iron chemical sys- ethyl vinyl alcohol (EVOH) lining. The oxygen permeability tems were employed. A sachet placed within the packaging of the master bag was less than 13 cc of oxygen per square bag contains chemical granules ranging from 0.001 mm to meter per 24 hours at 73 F. and 70% relative humidity. The 1.5 mm in diameter. The half-life of oxygen in a bag master bag was gas-flushed with different gas-compositions containing these oxygen scavengers was in the range of 30 and sealed.
to 1500 minutes, with the quantity of oxygen absorption [0087] The modified atmosphere characteristics were material ranging from 1 gram to 300 grams. The oxygen composed of different gas mixtures of carbon dioxide, absorption material was placed in a package, which was carbon monoxide, and nitrogen/inert gas. Typical gas mix-either laminated or unlaminated with porosity levels ranging tures either consisted of 100% nitrogen and/or any inert gas from 20 to 120 gurly a second, and an active surface area of or contained 100% carbon dioxide or different percentages 4 to 64 square inches. The preferred material for the bag is of gases generally in the concentrations of <1% carbon tyvek. The scavengers are typically formed from iron monoxide, <40% carbon dioxide, and the balance either (<25%, preferably 15-20%), carbon (<35%, preferably nitrogen and/or some other inert gas. The oxygen scavengers 20-30%), vermiculite (<20%, preferably 10-15%), and de-of different characteristics were placed in the master bags or ionized water (<10%, preferably 5%), salt [NaCI] (<10%, preferably 5%). A small amount (<10%) of zeolites can also in the retail trays or both. The residual oxygen content in the be added for increased oxygen absorption rates. Oxygen master bag after gas flushing using single or multiple cycles was less than 6%. The storage temperature of the master scavengers can also be based on magnesium, copper, and enzymes. The oxygen scavengers are activated upon expo-bags was less than 40 F., and the master bags were stored sure to air and/or oxygen in an atmosphere greater than 60% for up to 15 weeks.
relative humidity, and work under a temperature range of Display and Sampling of Retail-Trays 28 to 45 F.
[0088] Upon removal from primary storage at weekly Meat Characteristics intervals, and on day 0 of retail display, master packaging was removed and retail trays placed in the center of the [0083] The meat can be of any type such as pork, lamb, beef, veal, chicken, fish, turkey, venison, or any other meat display shelf. The displayed meat cuts were examined for discoloration, retail acceptability, off odor intensity, and type. In the actual meats studied developing the invention, odor acceptability, and odor description for every 24 hours meats used included beef, veal, pork, lamb, and chicken. The for up to nine days. A similar procedure was repeated for all cuts used were primal and/or sub-primal, and the grades of fresh meat cuts were prime, choice, and/or select. The meats storage intervals for up to 15 weeks.
included both boned and boneless cuts, and the size of fresh Visual Assessment of Master-Packaged Meat Cuts cut meat product was in the range of 1 to 5 lbs. The meat [0089] A five-member panel was used for the subjective carcass was cooled either though blast cooling and/or cold evaluation of the meat cuts. Surface discoloration was room storage, with a cooling temperature of between 5 to evaluated using a seven-point descriptive scale: 1..0%
40 E The time between slaughter and packaging was in the range of 24 hours to 120 hours. Packaging temperatures (none), 2-1-10%, 3-11-25%, 4..26-50%, 5-51-75%, 6..76-were less than 40 F.
99%, 7-100%. Retail appearance was assessed on a seven-point hedonic scale: 1-Extremely undesirable, 2-undesir-Retail Tray Characteristics able, 3-Slightly undesirable, 4-Neither desirable nor [0084] The retail tray composition was of plastic and/or undesirable. 5-Slightly undesirable, 6-Desirable, and 7=Ex-polystyrene and/or combination of both. The inherent oxy-tremely desirable.
gen content of the retail tray was in the range of 10 to 23,000 Odor Assessment of Master-Packaged Meat Cuts ppm. The surface of the retail tray exhibited either a grid or L0090] A five-member panel was used for odor assess-ridged pattern, or a flat surface upon which to place the fresh ment. Off odor intensity scores were assessed using a meat product. The retail tray cover was either lidded or four-point descriptive scale: 1-No off odor, 2-Slight off over-wrapped. The retail tray surface area was in the range of 15,000 to 325,000 square mm. A moisture absorbent pad odor, 3-Moderate off odor, 4-Prevalent off odor. Odor acceptability scores were assessed using a five-point scale:
was either placed in the retail tray before the fresh meat 1-Acceptable, 2-Slightly acceptable, 3-Neither acceptable product or was not included. The oxygen scavenger pads no unacceptable, 4-Slightly unacceptable, 5-Unacceptable.
were placed in the retail tray or exterior to the retail tray.
[0085] The retail tray overwrap used has an oxygen per-Microbial Analysis meability in the range of 3,000 to 10,000 cc of oxygen per [0091] A 10 cm' sample was obtained at each sampling square meter per 24 hours at 73 F. and 70% relative time (on day 0 and last day of each storage interval) from humidity. Additional atmospheric permeability of the retail each meat cut using a sterile cork borer. The sample was the US 2006/0228449 Al Oct.
12, 2006

7 placed into a stomacher bag with 10 mL of 0.1% peptone as an oxygen barrier under sub-zero temperatures and low solution and was massaged for 120 seconds using a corn- oxygen concentrations. Thus, the first phase of the invention mercial stomacher, yielding a dilution of 10 . The homogen- concentrates on the placement of oxygen scavengers posi-tate was further diluted 10-, 100-, and 10,000-, and 100, tioned inside the tray and being surrounded by the packaging 000-Ibld, after which 0.1 mI. volumes of undiluted film.
homogenate. Each dilution prepared was spread on duplicate [0100] In the second phase as illustrated in Example 2, the plates of All Purpose Tween (APT). The plates were then scavengers were interiorly placed within the trays containing incubated aerobically for 3 days at 25 C. The micro flora meat muscles. Here, the meat muscles had poor color was determined from plates bearing 20-200 colonies, stability since the packaging films covering the trays (seen Results Summary in Example 1) act as oxygen barriers under sub-zero tem-peratures and low oxygen concentrations. Hence, the pres-[0092] The oxygen concentration was 0 ppm (zero) after ence of 02 scavengers of appropriate capacity (at least 10 cc 24 hours of storage, and was 0 ppm throughout the storage per pound of meet) is required. During the second phase, period of up to 15 weeks. Based on sensory and microbial several experiments concentrated on the effect of varying the analysis: oxygen-absorbing capacities on the display life. Further, the [0093] 1) beef cuts were acceptable for 10 weeks storage need for knowing the initial concentration of oxygen in the plus 5 days at the retail display, package, calculating the needed half-life of oxygen in the package and subsequently designing the oxygen scavenger [0094] 2) pork chops were acceptable for 15 weeks during required to obtain the desired half life of oxygen.
storage plus 9 days at the retail display, [0101] Example 3 depicts the third phase of the present [0095] 3) lamb chops were acceptable for 8 weeks during invention whereby preventing transient discoloration of the storage plus 7 days at the retail display, and meat cuts, namely the retail-ready meat cuts. Lastly, the fourth phase as shown in Example 4 shows that the resto-ration 4) chicken pieces were acceptable for 8 weeks ration of metmyoglobin reducing activity will result in storage plus 6 days at the retail display.
extending the shelf-life of retail ready meat cuts. For Discussion example, the shelf-life of the retail-ready beef tender loin cuts was ten weeks with a display life of three days after [0097] Referring to FIG. 1, there are three chemical states each weekly storage differing from the conventional one to for myoglobin. Metmyoglobin is at a peak level at low two weeks with a display life of one and half days.
oxygen pressures of about 2 mm of mercury. At sea-level, the atmospheric pressure of oxygen is approximately 160 mm of mercury, while the total atmospheric pressure is approximately 760 mm of mercury. As can be observed Oxygen Absorption Kinetics of Enzymatic and Iron graphically, in order to begin minimizing formation of Chemical Systems Based Oxygen Scavengers metmyoglobin, the atmospheric partial pressure needs to be reduced to less than 1 mm of mercury, or an oxygen content [0102] The current uses of 02 scavengers generally at sea level of less than 0.13%. To have no metmyoglobin involve packs in which the atmosphere contains some sub-formation, the atmospheric partial pressure of oxygen needs stantial fraction of 02, if not air, at the time of pack sealing to be reduced to 0 rum mercury for an 02 content at sea-level and the inhibition of chemical reactions or proliferation of of 0 ppm (e.g. zero oxygen). microorganisms that proceed relatively slowly. Conse-[0098] Example 1 shown in Table IA depicts the first quently, commercial 02 scavengers are designed to remove a specified amount of 02 from a relative high 02 atmosphere phase of the present invention involving a detailed oxygen over periods of a day or more. 'The rate of 02 absorption has absorption study of oxygen scavengers based upon an iron then not been a principal concern in the design of commer-chemical system and enzymatic activity. The iron chemical cial 02 scavengers. However, there are applications such as system based scavengers are dependent upon the chemical centralized meat operations where the rate of 0, absorption reaction of ferrous iron to ferric oxide or ferric hydroxide.
is of prime importance.
Specifically, Example 1 indicates that oxygen scavengers modified based upon the iron chemical system have the [0103] The 02 absorption rates of 02 scavengers vary with potential for reducing the oxygen concentration to 0 ppm the natures of their reactants and other materials used in their within a few hours of master packaging, provided an appro- construction.
Rates of absorption may also be affected by priate selection of oxygen scavengers is combined with factors such as temperature and the compositions of the appropriate placement in the package. atmospheres to which they are exposed. Therefore, the objective of this study was to design an oxygen scavenger [0099] Two factors restricting the activity of the oxygen for centralized meat operation after studying the 02 absorp-scavengers are sub-zero temperatures such as ¨1.5 C. and tion kinetics of 02 scavengers based upon enzymes and iron a low oxygen concentration. Thus, the rate of the iron chemical systems.
chemical reaction is greatly reduced at subzero tempera-tures, and low oxygen concentrations prevent random move- Materials and Methods ment of oxygen molecules due to diffusion, which results in [0104] 1. 02 Scavengers lower oxygen absorption rates. Therefore, the activation of a custom-designed oxygen scavenger of an appropriate [0105] Self-activated 02 scavengers based upon iron capacity is capable of yielding short half-life of oxygen, i.e. chemical systems and enzymes were manufactured. Since a high rate of oxygen absorption. Furthermore, the packag- scavengers based upon iron chemical system may form ing film, preferably having a high oxygen permeability, acts carboxylic acid in the presence of CO, atmosphere, nitrogen US 2006/0228449 Al Oct.
12, 2006

8 atmosphere should only be used to obtain maximum oxygen calculating the volumes of 02 absorbed from each atmo-absorption rates from these scavengers, sphere of air by the scavenger, the initial volume of air was taken to be the 240 mL added to the pack plus the measured [0106] 2. Absorption of 02 by Scavengers volume of residual air. The volume of 02 in a pack at the end [0107] 02 scavengers were placed in gas impermeable of any period was calculated as the volume of atmosphere at bags composed of a laminate of polyester, oriented nylon, the end of the period multiplied by the concentration of 02 and an EVOH/EVA co extrusion with an 02 transmission in the atmosphere at that time. The volume of atmosphere at rate of 0.55 nil.. per m2 per 24 hours at 23 C., 70% relative the beginning of each period was taken to be the volume of humidity. Bags containing scavengers were either emptied atmosphere at the beginning of the previous period less the of air by flattening each bag around the scavengers it volume of the atmosphere removed as a sample at the end of contained, or were evacuated then filled with a known the period and the volume of 02 calculated to have been volume of N2 or CO2, using a controlled atmosphere pack- absorbed during the previous period.
aging (CAP) machine, before being sealed. Then, a quantity [0113] The volume of 02 absorbed during a period was of air was injected into each bag using a gas-tight syringe calculated as the volume of atmosphere at the start of the inserted through a stick-on septum (Modem Controls, Inc., previous period multiplied by the concentration of 02 in the Minneapolis, Minn., USA).
atmosphere at the beginning of the period less the volume of [0108] Immediately after the injection of air, the puncture- atmosphere at the start of the period multiplied by the point was sealed using a hot iron. Each filled bag was stored concentration of 02 at the end of the period. In calculating at room or a constant temperature. Samples (8 mL) of the the volumes of 02 remained in the pack in atmospheres of atmosphere in each bag were obtained every hour for 8 hours N2 or CO2 to which air was added, the volumes of the by means of a gas tight syringe inserted through a stick-on atmosphere removed during sampling and the volumes of 02 septum. If no substantial 02 absorption was noticed within absorbed during a period were neglected.
8 hours, samples were taken after every 12 hours for up to [0114] To determine the order of reaction, plots were 96 hours. Immediately after each sampling, the 02 concen-prepared of the natural logs (In) and the reciprocals of the tration in the sample was determined using an 02 analyzer volumes of 02 remaining in the pack atmosphere against (Mocon MS0750, Modem Controls, Inc., Minneapolis, time. If the In plot approximated a straight line, the reaction Minn., USA) with a zirconium oxide sensor, and the punc-ture-point regarded as first order. If the reciprocal plot approxi-mated was then sealed using a hot iron. Residual air in mated a straight line, the reaction was regarded as second the emptied bag was measured as the volume of water order. Rate-constants were calculated using the following displaced by the emptied bag, and was used in the calcula-equations:
tion.
[0109] To examine the effects of temperature and initial 02 concentrations on 02 absorption rates, scavengers were for first-order reactions-144k = ¨ki 4- In[A]o ¨ and placed in bags after the scavengers, in their original sealed package, had been held overnight at the temperature at for second-order reactions¨t= k +
[A
which 02 absorption was to be measured. For each of the two scavengers at each temperature, six bags were prepared.
Three of the bags were emptied of air, and sealed, and then [0115] where, [Allid t..amount of reactant A at time t(h), 240 inL of air was injected into each. The other three were each filled with 4.5 L of N2 before being sealed, and then 15 [0116] k-the rate-constant (hour), and mL of air was injected into each. For each of the two scavenger types based upon scavenging mechanism, two [0117] [A]o=the initial amount of reactant.
sets of six bags were prepared, with one set being stored at [0118]
Frequency factors and activation energies were each of the temperatures 25, 12, 2 or -1.5 C. calculated from the Arrhenius Equation of the form:
[0110] To characterize 02 absorption when 02 scavengers were placed inside over-wrapped retail trays within master packs, a 216x133x25 mm (LxWxH) retail tray over- inik) In(A) R T
wrapped with a film of 02 transmission rate of 8000 mL per m2 per 24 hours at 23 C., 70% relative humidity, containing scavengers, based upon iron chemical system, was placed in each of the six bags. AS mm hole was made at one comer [0119] where, of the over-wrapped film to allow free exchange of atmo- [0120] A-frequency factor (frequency of collisions), spheres during gas flushing, three bags were emptied of air .=
and sealed, and then 240 la of air was injected into each. [0121]
Eactivation energy (J
The other three bags were each filled with 4.5 L of N2 to [0122] It-universal gas constant (8.314 J mor 1 K-1), and which 15 mL of air was added by injection.
[0123] T.temperature (K).
[0111] 3. Data Analysis [0124] 4. Results p Using scavengers based upon iron [0112] The half-life of 02 in a pack atmosphere was chemical system in bags containing air, the 02 half-life was calculated as the time required for the 02 concentration in four times longer at -1.5 C. than at 25 C., but with a N2 the pack atmosphere to be reduced to half the initial value, atmosphere, the 02 half-life at -1.5 C. was only double that The half-life was calculated from the volumes of 02 at at 25 C. (Table IA) The 02 half-life in bags containing air successive time intervals during the storage of the pack. In and scavengers based upon enzymes was seven times longer US 2006/0228449 Al Oct.
12, 2006

9 at ¨1.5 C. than at 25 C., but was only two and a half times [0131] 2.
Master Packaging and Storage of Steaks and longer at ¨1.5 C. than at 25 C. with a N2 atmosphere. Chops (Table 1A) The 02 absorption reaction was first order for all [0132] Experiment 1: Ten fresh beef tenderloins (psoas the 02 scavengers. (Table 1B) major, PM) and twenty fresh pork loins (longissimus dorsi, Discussion LD) from animals slaughtered 24 hours previously, at local commercial beef-and pork-abattoirs, respectively, were [0125] The 02 concentrations affected the 02 half-lives obtained. The meat cuts were vacuum-packaged and stored substantially for any scavenger type resulting in longer 02 at 2 C. for 14 to 21 days and then used in the experiments.
half-lives for the low initial 02 concentration of 500 ppm in A total of 39 steaks and 39 pork chops were prepared from N, atmospheres than for the high initial 02 concentration of the stored samples.
200,000 ppm in air at the same temperature. Scavengers based upon iron chemical systems have shorter 02 half-lives [0133] Each steak or pork chop was placed on a solid than the scavengers based upon enzymes. The kinetic data of polystyrene tray with dimensions of 21 6x 1 33x25 mm the present study showed that the 02 absorption reaction was (LxWxH) containing 02 scavengers with 02 absorbing first-order at both high (20%) and low (500 ppm) initial 02 capacity of at least 10 mL per pound of meat and a single concentrations and included 02 concentration as a limiting absorbent pad.
Each retail tray was lidded with a shrinkable factor. film with an 02 transmission rate of 8000 mL per ni2 per 24 hours at 23 C., 70% relative humidity, using commercial [0126] At high initial 02 concentration, other t'actors, such glue. Two 3 mm holes were burned through the film in as the scavenger surface area and environment, may also opposite corners of each tray using a soldering iron to allow affect the 02 absorption rates. However, at low initial 02 free exchange of atmospheres during gas flushing. Three concentrations a diffusion-phenomenon, which is a deriva- retail trays were placed on a plastic cafeteria tray, which as live of 02 concentration, was the dominant influence and then placed in a 595x447 mm (LxW) bi-metalized, plastic resulted in low 02 absorption. A threshold 02 concentration laminate bag with an 02 transmission rate of 0.55 m2 per 24 existed where there was a dramatic decrease in 02 absorp- hours at 23 C., 70% relative humidity. The bag was then lion rate and 02 concentration became the primary limiting evacuated, filled with 2.5 L of N,, and heat-sealed using a factor for the 02 absorption rate. Consequently, different controlled atmosphere packaging (CAP) machine. Twelve rate-constants were observed for the same 02 absorption master packs each containing three steaks or three pork curve at the same temperature, depending upon initial 02 chops, were prepared and randomly allocated within species concentration. Therefore, the overall 0, absorption curve to different treatments including treatments where scaven-, produced by the scavenger was bi-phasic.
gcrs were placed either in retail trays or in the master [0127] The effect of the positioning of scavengers within package (Table 2a). Three retail trays containing steaks or packs was also substantial which suggests that despite its pork chops were not stored and served as controls.
high 02 permeability, the barrier film acted as an 02 barrier [0134] Master-packaged steaks and pork chops were at low 02 concentrations. Additionally, its barrier effect may stored at 2 C. for one week. The 02 concentration in each increase with decreasing temperature. Consequently, the master pack was then measured. The retail trays were then size of the hole in the lidding film is likely the limiting factor placed on retail display and evaluated for visual character-for 02 absorption when retail trays were placed in a bag.
istics by a 4-member trained sensory panel [0128] Due to significant variation in 02 absorption rates [0135] Experiment 2: Twenty-five beef rib-eyes (longissi-of 02 scavengers based upon iron chemical systems and mus thoracis, LT) from animals slaughtered 24 hours pre-enzymes, appropriate selection of 02 scavengers is of impor-viously were obtained from a local commercial beef-abattoir tance in situations where high 02 absorption is initially and were vacuum-packaged and stored at 2 C. Following required. For centralized meat operations, scavengers based storage for 3 weeks, steaks (96, 2 cm thick) were placed in upon iron chemical system should be employed. Also, total solid polyethylene trays with dimensions of 216x133x25 oxygen absorbing capacity of these oxygen scavengers mm containing 02 scavengers with 02 absorbing capacity of should be such that resulting oxygen half-life is less than two at least 10 ml. per pound of meat underneath an absorbent hours. However, due to significant positioning effects, they pad. Retail trays were lidded with a shrinkable permeable should be placed either inside the retail trays containing 02 film and were prepared as in Experiment 1. Four retail trays sensitive products, inside the retail trays as well as in the were placed on a cafeteria tray, which in turn was placed into surrounding gas-impermeable bags, or outside the retail tray a master-pack bag. The master-pack bags were evacuated, depending on the oxygen sensitivity of the meat cut.
filled with 3.25 L of N2, and heat-sealed using the CAP
machine. Six such packs were prepared containing one of four treatment combinations (G, II; Table 2a) and G2 and 112 (not given in Table 2a), which were over-wrapped instead of Testing of Different Master Packaging Options for lidded. Please note treatments, G2 and H2, differ from other Centralized Meat Operations treatments (G and H), by having retail trays over-wrapped Materials and Methods instead of lidded. The master-packs were stored and evalu-ated using procedures similar to those used in Experiment 1.
[0129] 1. Oxygen (02) Scavengers [0136] Experiment 3: Twenty-five Beef tenderloins (psoas [0130] 02 scavengers, based on iron-chemical systems, major, PM) from animals slaughtered 24 hours previously were used. These scavengers require moisture for activation were obtained from a local commercial beef-abattoir. Steaks and operating in air of N, atmospheres but not in CO, (2 cm thick) were placed in 216x133x25 turn-solid poly-atmospheres. ethylene trays containing 02 scavengers with 02 absorbing US 2006/0228449 Al Oct. 12, 2006 capacity of 200 mL (S2), 400 mL (S4), 600 mL (S6), or 800 [0146] b. Visual Properties m1, (S8) underneath an absorbent pad. Each retail tray was over-wrapped with a highly 02 permeable and shrinkable [0147] Pork color scores in all treatments ranged from 2.4 to 3.3, and would be considered normal except in treatment film as previously described. Containing the same treatment Dl, where the chops were slightly pale. (Table 2c) Chops in combination (S2, S4, S6, or 58), four retail trays were placed all treatments could be considered to be without discolora-in a master pack, which was evacuated, filled with 4.5 L of .
tton, except in treatments A and B, where the chops were N2, and heat-sealed using the CAP machine. Three retail slightly discolored. Chops in all treatments were rated trays served as un-stored controls.
desirable to extremely desirable except in treatments A, B, [0137] Following one week of storage at ¨1.5 C., the 02 and DI. Chops in treatment A were rated slightly undesirable concentration in each master pack was measured as previ- and chops in treatments 13 and DI were rated slightly ously described. All master bags were removed and the retail desirable.
(Table 2c) Beef steaks in all treatments were trays were placed on retail display and evaluated for visual perceived to be bright cherry red to moderately dark red, characteristics daily tbr four days. except in treatments E and GI, where color scores were reduced due to complete discoloration of one or more steaks.
[0138] 3. Display and Evaluation of Retail Trays Steaks in all treatments without 02 scavengers either inside [0139] All retail trays were placed at the center of the the retail tray or in the master pack were moderately discolored. Steaks in treatments H and G1 were also mod-display shelf. Displayed steaks (PM or LT) and pork chops erately discolored, undoubtedly as a result of 02 ingress (LD) were evaluated for color, extent of discoloration, and through the pack. Steaks in all treatments with 02 scaven-retail appearance 30-45 min after master pack opening by a ers inside the retail tray were perceived to be at least 4-5 member trained sensory panel. The details of the eight- g slightly desirable, except in treatments H and G1 , due to point descriptive scale for the color of beef, the six-point extensive discoloration as a result of apparent 02 ingress.
descriptive scale for the color of pork, the seven-point descriptive scale for discoloration of both beef and pork, and (Table 2c and FIG. 2A) the seven-point heclonic scale for retail appearance for both [0148]
Comparison of retail appearance scores for beef beef and pork are given in Table 2c. Reflectance spectra steaks stored with and without 02 scavengers indicates the from the meat surfaces were obtained to estimate the pro- necessity of including 02 scavengers in master packaged, portions of metmyoglobin, deoxymyoglobin, and oxymyo- display ready meat cuts, stored in controlled atmospheres.
globin. Comparison of treatments D and F with DI and Fl for beef clearly demonstrates the 02 scavengers should be positioned [0140] 4. Estimation of the Oxidative Status of Myoglobin inside the retail tray. (Table 2c) [0141] Each retail tray containing a steak or a chop was [0149] c. Chemical States of Myoglobin evaluated by reflectance spectrophotometry (Macbeth Color eye 1500/Plus, Kollmorgen Corp., Newburg. N.Y., USA), at [0150] Pork chops in all treatments previously stored with three anatomical locations on each cut. Proportions of the 02 scavengers had 62.0% or more oxymyoglobin and essen-different chemical states of myoglobin (deoxy-, met-, and tially 0.0%
metmyoglobin when displayed in air, except in oxy-) were estimated using standard procedures, by con- treatments G and HI. Chops in treatment G had 2.1% and verting the readings (R) to K/S values [K is the absorption chops in treatment H1 had 6.8% metmyoglobin. (Table 2d) coefficient and S is the scattering coefficient, determined at Beef steaks in treatments containing 02 scavengers had selected wavelengths using the formula: K/S.(1¨R)2/2R]. >90.0%
oxymyoglobin, and <2.5% metmyoglobin, except in Ratios of wavelengths used for calculations are: K/S treatment H and GI .
Steaks in treatment H had 78.5%
4744-K/S 525 for % deoxymyoglobin, K/S 572+K/S 525 for oxymyoglobin and 7.8% metmyoglobin; and steaks in treat-% metmyoglobin, and K/S 610+.K/S 525 for A oxymyo- meat GI had 58.9%
oxymyoglobin and 37.3% metmyoglo-globin. bin, presumably as a result of 02 ingress into the package.
(Table 2d) This data confirm the visual data and the require-[0142] 5. Statistical Analysis ment for 02 scavengers inside the retail tray when master packing display-ready meat cuts in controlled atmospheres.
[0143] The influences of different treatments on factors influencing meat color were compared statistically for sig-nificant differences (p<0.05) using Analysis of Variance Experiment 2 (Proc ANOVA and LSD means) in SAS (SAS Institute Inc., [0151] a. Oxygen Concentration Car)', N.C., USA).
[0152] The initial 02 concentration in every fifth bag was Results about 120 ppm.
[0153] After one week of storage, the 02 concentration in Experiment 1 all bags was 0 ppm, except for one bag (Bag 2, treatment H) [0144] a. Oxygen Concentration which contained 2650 ppm 02 and was a "leaker" and was consequently eliminated from further evaluation.
[0145] The 02 concentration in every fifth bag at initial packaging was 150-200 ppm. After being stored for one [0154] b. Visual and Reflectance Properties week at 2 C. the 02 concentration in most bags with 02 [0155] Although significant (p<0.05) differences existed scavengers was 0 ppm, except for bags with treatments H, G, between treatments in visual color ratings, all steaks were and GI with beef (Table 2b). Bags without 02 scavengers perceived to be bright cherry red and no differences of contained small amounts of 02, occasionally up to 1150 practical importance existed. Retail trays containing grids ppm. resulted in steaks with greater amounts of surface discol-Oct. 12, 2006 US 2006/0228449 Al oration. However, no differences in surface discoloration study. The appropriate absorbing capacity 01 02 scavengers attributable to lidding or over-wrapping were detected. to be used appears to be >600 mL based upon present results.
(Table 2c) Consequently, steaks in retail trays containing [0163] Steaks and chops used in the present study were grids were rated less desirable in retail appearance (p<0.05).
vacuum-packaged and stored for two to three weeks at 2 C.
lowever, the magnitudes of these differences in retail before master packaging, which lowers their metmyoglobin-appearance were approximately 0.8 of a panel unit making reducing capacity, and therefore presented a worst-case them of only marginal practical importance. (FIG. 2B) scenario for centralized packaging operations.
[0156] Steaks in over-wrapped trays containing a grid had [0164] Therefore, greater storage ability should be the highest proportions of oxymyoglobin and the lowest expected with fresh, un-stored beef or pork. Although pork proportions of metmyoglobin (p<0.05). Despite this finding, can probably be master packaged using any treatment-the visual data clearly indicates inclusion of a grid in the tray combination with 02 scavengers, the presence of 02 scav-is not so productive, and the overall data clearly demon-engers inside the retail tray appears to be imperative when strates similar advantages for either lidding or over-wrap-master packaging beef. Treatments G, G2, H, and H2 were ping the trays. Consequently, the most feasible retail pack-selected as retail packaging systems, which may be corn-aging system for use with controlled atmosphere, master mercially adaptable. Additional replicates of each of these packaging is the over-wrapped tray containing 0, scavengers treatments were evaluated in part II of the present study to underneath an absorbent pad. (Table 2c) determine the importance of a grid inside the retail tray and to obtain a comparison of lidded and over-wrapped retail Experiment 3 trays. Results indicated a grid was not required and there [0157] a. Oxygen Concentration was little difference between lidded and over-wrapped trays.
(Table 2c) With CAP master-packages, selection of an [0158] The 02 concentration at packaging was approxi- appropriate retail packaging system should include an mately 80 ppm. After 7 days of storage at ¨1.5 C., the 02 assessment of the number of 02 scavengers required in each concentration in all bags was 0 ppm. retail tray to minimize residual 02 concentrations.
[0159] b. Visual and Reflectance Properties [0165] High 02 -permeable film over-wrap has been shown [0160] Steaks in retail trays containing 02 scavengers with to act as an 02 barrier at low 0, concentration. Conse-absorbing capacity of <600 mL were more discolored than quently, two isolated systems affect the 02 concentration in the un-stored controls at all display intervals, but discolored the overall package-atmosphere of master packs. The prob-essentially the same rate as the un-stored controls. (FIG. ability of having 02 entrapped inside the retail tray is high 2C) Steaks in retail trays containing 02 scavengers with 800 due to the absorbent pad and space between over-wrap and mf, of absorbing capacity also discolored at essentially the edges of the tray.
same rate as the un-stored controls, but did not discolor as [0166] The amount of 02 absorbing capacity in each retail extensively. Tin-stored controls deteriorated rapidly in retail tray will also dictate the retail display life of meat cuts.
appearance and had a retail case-life of 2.5 days. (FIG. 2D) Steaks packaged with higher absorbing capacity, i.e., with a Steaks stored with less than or equal to six 02 scavengers high absorbing capacity 02 scavengers tend to have more resulting in 02 absorbing capacity of less than 600 mL also retail display life than those packaged with low absorbing deteriorated rapidly in retail appearance and had shorter capacity 02 scavengers. As the present study demonstrated, retail-case lives than un-stored controls. Steaks stored with longer retail display life for steaks packaged with 02 scav-02 scavengers having absorbing capacity of >600 mL dete-engers of absorbing capacity >600 mL are achieved relative riorated more slowly in retail appearance and had retail-case to 02 scavengers of low capacity. The higher the absorbing lives in excess of 4 days. (FIG. 2D) The rate of metmyo-capacity, the shorter the 02 half-life is in the pack atmo-globin and oxymyogloin (% oxymyoglobin-100-% met-sphere, resulting in faster removal of residual 02, which in myoglobin) fotmation during retail display (FIG. 2E) turn prevents transient discoloration. With prevention of clearly demonstrates the advantage of using 02 scavengers transient discoloration, the limited metmyoglobin reducing and indicates a minimum requirement for 02 scavengers capacity of the muscle is preserved. This activity further with absorbing resulting in an 02 half-life of 0.6-0.7 hours delays development of discoloration during retail display in the pack atmosphere, where the 02 concentration could and yields acceptable retail appearance even after four days otherwise remain less than or equal to 500 ppm at any time of retail display, as shown in the present study. (Table 2c) during storage (a deficiency noted in prior art methods).
[0161] C. Discussion [0167] The present study further demonstrated little importance for placing meat cuts on a grid and little advan-[0162] At low temperatures pork color is stable at several tage for lidding retail-trays. However. 02 scavengers based hundred ppm of 02. The present study confirmed this upon iron chemical system with oxygen absorbing capacity finding. (Table 2c) Beef, especially PM, discolors even at ?:-. 600 ml, must be placed inside the retail trays to attain an very low 02 concentrations, which is also evident from the 02 concentration of 0 ppm in the pack atmosphere of a results of the present study. The present results clearly master pack of the size 595x447 mm. The number of 02 demonstrate 02 scavengers arc essential to prevent and/or scavengers can vary provided they can provide an 02 reduce discoloration in master-packaged meats. The use of half-life of 0.3-0.4 hours in the master pack. Another corn-02 scavengers in master packing of pork should provide bination, depending upon the color stability of meat cuts, protection to complement the intrinsic ability of pork muscle can be placing some oxygen scavengers in the master pack tissue to resist oxidative discoloration and may provide (outside the retail tray) and only a few in the retail tray.
increased display life. The use of 02 scavengers reduced 02 However, the commercial system that can deliver a total concentrations to 0 ppm in most treatments in the present storage and shelf-life of retail-ready eat cuts should have US 2006/0228449 Al Oct. 12, 2006 clear plastic tray with oxygen scavengers underneath the sions 152x114 mm in a 216x133x25 mm solid polystyrene absorbent pad, and the meat cuts placed on top of the tray. 02 scavengers with 02 absorbing capacity of at least 10 absorbent pad. (Table 2c and FIG. 2D) cc per pound of meat product were placed underneath the absorbent pad. Each retail tray was over-wrapped with a EXAMPLE 3 shrinkible film having an 02 transmission rate of 8000 mL/(m 24 hour) at 23 C. and 70% relative humidity.
Prevention of Transient Discoloration of [0175] After sealing, the film was shrunk to the tray using Retail-Ready Beef Cuts a hot-air gun. Two 3-mm holes were made in the film at the corners of the tray to allow free exchange of atmospheres [0168] Centrally-prepared retail beef cuts stored in con-during gas flushing. Four such retail trays were placed in a trolled atmospheres containing nearly 100% carbon dioxide 595x447 mm bimetalized, plastic laminate pouch. The mas-(CO2) or nitrogen (N,), which may have small amounts of ter packs were evacuated, filled with 4.5 L N2, and sealed 02, are susceptible to the formation of metmyoglobin due to the presence of the residual 02. If the 02 concentration is not using a CAP
machine. Eight such master packs were pre-excessive, the meat will absorb the residual 02 and any pared. Similarly, eight master packs, each having four retail t metmyoglobin formed will be reduced to deoxymyoglobin rays containing two of another type of 02 scavengers underneath the absorbent pads; and an additional eight as a result of metmyoglobin reducing activity (MRA) within the muscle tissue. In packaged fresh beef 2-4 days are master packs, each containing four retail trays with no 02 scavengers (controls), were prepared. Each pack was labeled required for reduction of metmyoglobin to deoxymyoglobin.
When stored meat is removed from the controlled atmo-accordingly.
sphere, it blooms to the desirable, bright, red color associ- [0176] The master-packaged steaks were stored at 1 0.5 ated with freshly cut meat, but this will not occur if a C. On day 0, four retail trays served as fresh controls and substantial amount of metmyoglobin is present. The MRA of were kept for visual evaluation in the retail-display case and muscle tissue is limited and once exhausted cannot convert to obtain reflectance spectra of the steak surfaces. Three any metmyoglobin formed back to myoglobin. This results master packs (one having one type and another one having in inevitable transient discoloration problem. another type of 02 scavengers, and one having no 02 [0169] Transient discoloration of meat is not a major scavenger), were opened at 1 day intervals for 8 days and placed in a retail display case. The 02 concentration in each concern when the product is in storage. transit. or both for long periods. However, such discoloration is highly unde-pack was measured immediately before being opened.
sirable when commercial conditions require periodic rapid [0177] 3. Display and Sampling of Retail Trays distribution and display of centrally packaged meat. Conse-quently, premature temporary discoloration limits the advan- [0178] All retail trays were placed in the center of the tages of centrally packaged retail ready meat cuts using display shelf of a horizontal, fan-assisted retail display case.
02-depleted master packaging technology. Such discolora- The PM steaks on display were examined for color, disco].
tion is also dependent upon the specific muscle packaged oration, and retail appearance at 30-45 min after opening of since tissues vary in their capacity to withstand "low" 02 the master-packs, and reflectance spectra of the steak sur-concentrations (<500 ppm). Centrally prepared beefsteaks faces were obtained to estimate metmyoglobin, deoxymyo-and ground beef packaged under controlled atmospheres globin, and oxyuayoglobin content.
were shown to be susceptible to very low 02 concentrations.
[0179] 4. Visual Assessment of Master-Packaged Steaks Beef muscles with high color stability (LD) are least sus-ceptible to metmyoglobin formation if atmospheres con- [0180] A five-member trained panel was used for the tamed <600 ppm of 02 at temperatures <0 C. however, subjective evaluation of the steaks. Surface discoloration beef with poor color stability (PM) was highly susceptible to was evaluated using a seven-point descriptive scale: 1-.0%
metmyoglobin formation even at very low 02 concentrations (none), 2=1-10%, 3-'11-25%, 4=26-50%, 5-51-75%, 6=76-and sub-zero temperatures. 99%, 7-100%. Retail appearance was assessed using a seven-point bedonic scale: I -extremely undesirable, 2.un-[0170] The objective of this study was to determine desirable, 3-slightly undesirable, 4-neither desirable nor whether 02 absorbent technology might be used in conjunc-undesirable, 5-slightly desirable, 6-desirable, 7-extremely tion with CAP to prevent inevitable transient discoloration of PM beef. desirable.
Materials and Methods [0181] 5. Estimation of Myoglobin States [0171] 1. Oxygen Scavengers [0182] The average reflectance spectrum was obtained from three locations of the steak covered with a shrinkable [0172] 02 scavengers, based on iron chemical systems, film using a reflectance spectrophotometer. Reflectance val-and having 02 absorbing capacity of at least 10 cc per pound ues (R) of the different myoglobin oxidation states were of meat product were used in the study, estimated at specified wavelengths, and converted to K/S
[0173] 2. Master Packaging, Storage, and Sampling of values (K is the absorption coefficient and S is the scattering Steaks coefficient). The K/S values are used for quantifying the proportion of deoxy-met-, and oxy-myoglobin, and are [0174] Twenty fresh beef tenderloins (psoas major, PM) calculated using selected wavelengths (474, 525, 575, and from animals slaughtered within 24 hours were obtained 610 nin) for fresh meat color. The ratios and wavelengths from a local beef 'packing plant. Four 2 cm thick steaks were used for the calculations were: K/S 474+ K/S 525 for percent prepared from each tenderloin and were randomly distrib- deoxymyoglobin, K/S 575+K/S 525 for percent metmyo-uted. Each steak was placed on an absorbent pad of dimen- globin, and K/S
610+K/S 525 for percent oxymyoglobin.

US 2006/0228449 A 1 Oct.
12, 2006 [0183] 5. Statistical Analysis scavengers after 3 and 7 days of storage (p<0.05). Differ-ences were most noticeable at 2, 3, 6, and 7 days of storage, [0184] The effects of treatment differences (control and where the metmyoglobin content of steaks packaged with both types of 02 scavengers) were examined statistically type-II 02 scavengers was reduced to zero. (FIG. 3C) using analysis of variance (proc ANOVA, SAS Institute, Inc., Cary, N.C.) at a level of 0.05. Only the main effects Discussion were analyzed.
[0192] Reduced 02 concentration has been demonstrated Results to have an adverse effect on meat color, and PM has been [0185] a. Visual Assessment of Steaks shown to have the least color stability, discoloring rapidly even at very low 02 concentrations (<100 ppm) irrespective [0186] Discoloration: On day 0, all steaks received dis- of the storage temperature. Consequently, 02 absorbent coloration scores of 1 (00/u: discoloration). After subsequent technology might be used in conjunction with CAP to daily storage intervals, steaks packaged with no 02 scaven- prevent inevitable transient discoloration, and this consti-gers had discoloration scores of either 2 (1-10% discolora- tuted the hypothesis of the present study. On day 0, the 02 tion), 3 (11-25% discoloration) or 4 (26-50% discoloration) concentration was 78 ppm and this rose to 477 ppm in (Table 2c). Steaks packaged with type-one 02 scavengers master packs without 02 scavengers after 1 day of storage.
received a discoloration score of 1 (0% discoloration) after 2, 4, 7. and 8 days, and 2 (1-10% discoloration) after 1, 3, [0193] Master packs containing 02 scavengers had no 5, and 6 days. Steaks packaged with type-two 02 scavengers measurable 02 at most storage times, except after 1 and 2 received discoloration scores of 1 (0% discoloration) at days in the case of type-I 02 scavengers. As a consequence, storage intervals of 1, 2, 4, 6 and 8 days, and discoloration steaks with 02 scavengers had low metmyoglobin content scores of 2 (1-10% discoloration) at storage intervals of 3, and almost no discoloration, which resulted in significantly 5, and 7 days (FIG. 3A). higher RA scores. Steaks packaged without 02 scavengers had an increase in metmyoglobin content from day 0 to day [0187] Retail Appearance (RA): On day 0, control steaks 3 of storage. After 4 days storage, metmyoglobin content received retail appearance scores of 7 (extremely desirable), decreased, but then gradually increased until after 7 days After subsequent daily storage intervals, steaks packaged storage, when it decreased again. This indicated these steaks with no 02 scavengers received RA scores of 5 (slightly underwent two cycles of transient discoloration, regaining desirable) or 6 (desirable) after 1, 2, 5, and 7 days. However, color due to MRA or other reducing factors.
these scores were down to 3 (slight undesirable) or 4 (neither desirable nor undesirable) after 3, 4, 6, and 8 days of storage. [0194]
Steaks packaged with 02 scavengers did not Steaks packaged with type-one 02 scavengers received RA undergo such transient discoloration. Moreover, steaks scores of 6 (desirable) or 7 (extremely desirable) for all packaged with type-II 02 scavengers had lower metmyo-storage intervals, and steaks packaged with type-II 02 globin content than the fresh control after all storage inter-scavengers received RA scores of 6 or 7 for all storage vals, and metmyoglobin content was reduced to zero in some intervals, except after 7 days when they received RA scores cases. In the present study. PM steaks expected to have poor of 5 (slightly desirable) (FIG. 3B). color stability were used, but, very low metmyoglobin contents and high RA scores were observed in samples [0188] b. Metmyoglobin on the Steak Surface packaged with 02 scavengers.
Thus, the hypothesis of com-[0189] Metmyoglobin content was not significantly differ- bining 02 absorbent technology with CAP to prevent tran-ent for control steaks (with no 02 scavengers) after most sient discoloration was proven. (FIGS. 3B and 3C) storage intervals when compared to fresh controls (p0.05), [0195] The 0, concentration during initial packaging was except after 3 and 7 days. Metmyoglobin content increased 78 ppm, and it went up to 477 ppm after 1 day of storage.
from 3.5% on day 0 to 22.8% on day 3, then decreased to Therefore the amount of time required to reduce the 0, 4.7% on day 4, and again increased to 16.1% on day 7 but concentration from 477 ppm to 0 ppm would be almost four decreased to 5.2% on day 8. (FIG. 3C) Discoloration was times the half-life of 0, in the package atmosphere. For visible at the edges of these steaks for all storage intervals, ti type-I and type-II 02 scavengers, incorporating the number However, these areas were not exposed during reflectance of scavengers used in the study, the 02 half-life is 0.31 and spectrophotometry, and thus, the reflectance spectra did not 0.65 hours, respectively (Example 1). Steaks will also con-report this discoloration, which would have undoubtedly increased the proportion of inetmyoglobin. (FIG. 3C) tribute to the total 02 absorbing capacity to some extent (<10%). Thus, at 1 0.5 C., transient discoloration of PM
[0190] Metmyoglobin content of steaks packaged with steaks can be prevented if residual 02 is reduced to 0 ppm type-I 02 scavengers was not significantly different when within 3 hours of pack closure.
compared to control steaks (steaks packaged with no 02 [0196] Selection of ,a suitable retail-packaging system is scavengers), for all storage intervals (p>0.05), except after 3 and 7 days of storage. Also, the metmyoglobin content was another critical aspect of master packaging technology using comparable with that of the fresh control for all storage CAP. It is evident from the results of the present study that intervals (p>0.05). (FIG. 3C). the 02 concentration in the master pack may initially increase drastically after packaging. Such an increase may [0191] The metmyoglobin content of steaks packaged be attributed to 02 entrapment either in the absorbent pad or with type-ll 02 scavengers was not different when compared under the over-wrap film during evacuation. In addition, with fresh controls and steaks packaged with type-II 02 meat tissue itself initially releases dissolved, unreacted 02 scavengers, for all storage intervals (1>0.05). However, causing reduction of oxymyoglobin to deoxymyoglobin in steaks packaged with no 02 scavengers had higher metmyo- the presence of low partial pressures of 02 in the head space globin content than the steaks packaged with type-II 02 during CAP storage.
This increase is inevitable. Therefore, US 2006/0228449 Al Oct.
12, 2006 02 entrapment must be minimized to prevent 02 concentra- storage and retail display life of master packaged beef steaks tions increasing in the pack to the point where transient (PM) stored under 100% nitrogen atmosphere along with 02 discoloration may occur. absorbents at -1.5 C.
[0197] It has been found that over-wrap film with high 02 Materials and Methods permeability acts as an 02 barrier at low initial 02 concen-trations (Example 1), and the barrier property increases at [0201] 1.
Oxygen Scavengers low storage temperatures. It is also evident that 02 concen- [0202] 02 scavengers, based on iron chemical system, tration may increase due to entrapment of 02 in either the were used in the study. The 02 absorbing capacity was at absorbent pad or the over-wrap. It is recommended that each least 10 mL per pound of meat.
retail tray within the master pack contain 02 scavengers to absorb any 02 entrapped inside tray, which may affect meat [0203] 2. Master Packaging, Storage, and Sampling of Steaks color. Less discoloration occurs on steak surfaces in a system where 02 scavengers are placed in the master pack. [0204] Fresh beef tenderloins (psoas major, PM) from Placing 02 scavengers directly inside the retail tray will also animals slaughtered 24 hours previously were obtained from reduce the number of 02 scavengers required, a local beef abattoir. Eighty steaks of 2 cm thickness were prepared from these tenderloins. Each steak was placed on [0198] The present work was designed to examine meat a 152x114 mm absorbent pad in a 216x133x25 mm (LxWx samples with the highest pigment instability stored under H) solid polystyrene tray with 02 scavengers having 02 conditions conducive to discoloration during centralized absorbing capacity of at least 10 mL per pound placed distribution. Beef (PM) was placed in over-wrapped retail underneath the absorbent pad. Each retail tray was over-trays (which may have 02 entrapped in the absorbent pad or wrapped with a shrinkable 02 permeable film with an 02 over-wrap or both). Although a storage temperature of 1 0.5 C. is not recommended to optimize storage life of transmission rate of 8000 mUm2 per 24 hours at 23 C., 70%
relative humidity, and atmospheric pressure. After sealing, fresh meat cuts in centralized systems, it is closer to the the film was shrunk to the tray using a hot-air gun. Then, two optimum (-1.5 C.) than the commercial norm. Rates of 3-mm holes were made at the opposite corners of the tray to myoglobin oxidation and metmyoglobin reducing activity allow for exchange of atmospheres during gas flushing. Four increase and decrease, respectively, at temperatures above 0' such retail trays were placed in an EVA co-extruded master C. Thus, better results can be expected at -1.5 C. Never-pack with 0, transmission-rate of 0.55 mUm2 per 24 hours theless, under worst-case conditions, the use of 02 scaven-at 23 C., 70% relative humidity. and atmospheric pressure.
gers in conjunction with CAP prevented transient discolora-lie bags were evacuated, filled with 4.5 L of N2, and sealed tion of PM beefsteaks. It is probable that the system used in using a CAP machine. Twenty such bags were prepared.
the present study will easily prevent transient discoloration in beef steaks with higher color stability, such as LD, Additionally, 8 retail trays were prepared and treated as especially if stored below 0 C. Oxygen scavengers should un-stored controls.
prevent transient discoloration of all centrally prepared beef [0205] The master packs were stored at -1.5 0.5 C. On cuts, but, factors such as selection of packaging systems, 02 week 0 and day 0 of retail display, four steaks in retail trays.
scavenger type, and package atmospheres (N2/CO2) may serving as fresh, un-stored controls, were analyzed for affect results. visual, odor, taste, and microbial characteristics. Also, reflectance spectra were obtained from the surface of these EXAMPLE 4 steaks. The visual analysis was done daily for 4 days. and similarly reflectance spectra were obtained daily. On day 4 Total Shelf Life of Retail-Ready Meat Cuts Using of retail display, odor, taste, and microbial analyses were the Designed Packaging System and Optimized done in addition to visual examination and reflectance Oxygen Absorption Technology spectra measurements. Two master packs were opened at subsequent 1 week storage intervals for 10 weeks. The 02 [0199] Exploration of an appropriate master-packaging concentration in each bag was measured immediately before system, which will minimize both color instability and opening the bag.
microbial spoilage. is imperative for centralized meat opera-tions. Although research has been done on microbiological [0206] Master-bags containing meat cuts and oxygen and sensory aspects of meat during centralized meat pack- scavengers having oxygen absorbing capacity of at least 10 aging under various modified atmospheres, meat discolora- mL per pound of meats, placed only outside the meat-trays, tion due to residual 02 in controlled atmospheres remained were also prepared. The over-wrap film of the meat-trays a challenge as the rate of metmyoglobin formation increases had at least one hole of less than 5 mm diameter. Such at low partial pressures of 02. master-bags were flushed-back with a gas-mixture contain-ing 64.6% Nitrogen. 0.4% CO, and 35% CO,.
[0200] Beef steaks made from muscles of poor color stability, such as psoas major (PM), discolor rapidly even at [0207] 3.
Display and Sampling of Retail Trays 02 concentrations of <100 ppm and sub-zero temperatures, [0208] Upon removal from primary CAP storage at resulting in short storage life in CAP followed by short weekly intervals, and on day 0 of retail display, master display life. Consequently, application of oxygen absorption packaging was removed and each group of 8 retail trays was technology in conjunction with CAP became an attractive option. In addition, a suitable retail packaging system is placed in the center of the display shelf:
required to reduce residual 02 in the controlled atmospheres [0209] The displayed PM steaks were examined for color.
due to the possibility of 02 entrapment within retail trays. discoloration, retail-acceptability, off odor intensity, odor The objective of the present study was to examine the acceptability, and odor description, 45 min after opening of US 2006/0228449 Al Oct.
12, 2006 the master-packages. Also, reflectance spectra from the steak Results surfaces were obtained to estimate metmyoglobin, deoxy-[0219] a. Measurement of 02 Concentration myog,lobin, and oxymyoglobin. After visual scores and reflectance spectra were obtained, two steaks (one from each [0220] The 02 concentration was <100 ppm at initial master bag) were removed from the display case, and packaging, and after any CAP storage interval it was reduced samples were taken for microbial analysis. Then the steaks to 0 ppm, except after 8 weeks storage when 24 ppm of 02 were cooked and analyzed for flavor acceptability and was measured in one bag.
off-flavor intensity. [0221] b. Evaluation of Steaks [0210] The remaining six steaks were left in the display [0222] Although significant (p<0.05) differences existed case, and were examined for visual characteristics at sub- between CAP
storage intervals in visual color rating on day sequent intervals of 24 hours and reflectance spectra at 12 0 of retail display, that is, when steaks were removed from hours for 96 hours. Aftcr 96 hours of retail display, the steaks storage, all steaks were perceived to be bright cherry red or were analyzed in a similar fashion as on day 0 of retail slightly dark red and no differences of practical importance display. During sensory evaluation, the samples remained in existed.
Generally, steaks remained stable in color until they the display case and the well-trained panelists made judg- became extremely dark (FIG. 4A) or completely discolored ments independently. A similar procedure was repeated for (data not shown) on the fourth day of retail display for any all storage intervals, storage interval. Due to a leak in the master pack, steaks were completely discolored on day 1 of retail display after [0211] 4. Visual Assessment of Master-Packaged Steaks 1 week of storage. These steaks were removed from retail [0212] A five-member panel was used for the subjective display and not analyzed further.
evaluation of the steaks. Color scores were assessed using an [0223] On day 0 of retail display for any CAP storage eight-point descriptive scale: 0-Completely discolored, interval, no significant (p>0.05) surface discoloration was 1-White, 2-Pale pink, 3-Pink, 4-Pale red, 5=Bright cherry reported on the steaks. The retail display period significantly red. 6-Slightly dark red, 7-Moderately dark red, 8-Ex-(p<0.05) increased the amount of surface discoloration on tremely dark red. Surface discoloration was evaluated using the steaks for any CAP storage interval. However, the steaks a seven-point descriptive scale: 14% (none), 2=1-10%, discolor 3-11-25%, 4=26-50%, 5=51-75%, 6=76-99%, 7-100%. discolored at a faster rate than the un-stored controls for all storage intervals, and were relatively extensively discolored Retail appearance was assessed on a seven-point hedonic (p4).05). (FIG. 4B) scale: 1-Extremely undesirable, 2-Undesirable, 3-Slightly undesirable, 4-Neither desirable nor undesirable, 5-Slightly [0224] Steaks were extremely desirable in retail appear-desirable, 6-Desirable, 7-Extremely desirable. ance on day 0 of retail display for any storage interval (p>0.05). Despite the fact that they deteriorated more rapidly [0213] 5. Odor Assessments of Master-Packaged Steaks in retail appearance than the un-stored controls, they were [0214] A five-member panel was used for the odor assess- still in the acceptable range (about 3.5) on the third day of ment. Off odor intensity scores were assessed using a retail display. (FIG.
4C) four-point descriptive scale: 1-No off odor, 2-Slight off [0225] From a practical perspective, steaks were perceived odor, 3-Moderate off odor, 4-Prevalent off odor; odor to have no off-odors on day 0 of retail display for any storage acceptability scores were assessed using a five-point scale: interval, however, significant differences existed between 1-Acceptable, 2-Slightly acceptable, 3-Neither acceptable storage intervals with respect to off odor intensity ratings nor unacceptable, 4-Slightly unacceptable, 5-Unaccept- (p<0.05). The maximum difference in ratings was 0.3 of a able; and off odor description scores were assessed using a panel unit, which is of marginal practical importance. Even six-point scale: 1-Sour-sulfur rotten eggs), 2-Sour-lactic on day 4 of retail display, only slight off odors were reported.
acid, 3-Putrid, 4-Dirty socks, 5-Floral/Fruity, 6-Other. (FIG. 4D) Generally, odor of steaks was acceptable on day [0215] 6. Microbial Analysis 0 of retail display. (FIG. 4e) Maximum differences of 0.3 of a panel unit were noticed after 7 and 8 weeks of CAP
[0216] A 10 cm2 sample was obtained at each sampling storage, which has little practical significance. Despite sig-time (on day 0 and 4 of each storage interval) from each of nificant (p<0.05) differences between storage intervals on the two steaks using a sterile cork borer. Then, the sample odor acceptability ratings of day 4 of retail display, all steaks was placed into a stomacher bag with 10 mL of 0.1 % were perceived to be slightly acceptable. (FIG. 4E) peptone solution and was massaged fur 120 seconds using a [0226] Despite differences (p4).05) between CAP storage commercial stomacher, yielding a dilution of 100. The =
intervals on microbial numbers at day 0 of retail display, homogenate was further diluted 10-, 100-, 10,000-, and steaks had <102 cfu/cm2 of total organisms, and no differ-100,000-fold, after which 0.1 mL volumes of undiluted ences of practical importance existed. In most cases, micro-homogenate and of each dilution were prepared and were bial numbers were comparable with those of un-stored spread on duplicate plates of APT. The plates were incubated controls.
(FIG. 4F) On day 4 of retail display, microbial aerobically for 3 days at 25 C. The micro flora was numbers were <100 cfu/cm2 in all cases. (FIG. 4F) When determined from plates bearing 20-200 colonies.
opened. meat-cuts in master-bags containing 0.4% CO
[0217] 7. Statistical Analysis bloomed quickly when compared with meat-cuts in master-bags containing 100% nitrogen.
[0218] The main effects of storage interval and retail 0227] C. Discussion display period were examined statistically using analysis of 1 -variance (proc ANOVA, SAS Institute Inc., Cary, NE.) at an [0228] Centrally prepared retail beef cuts stored in con-a level of 0.05. trolled atmospheres containing nearly 100% carbon dioxide US 2006/0228449 Al Oct.
12, 2006 (CO2) or nitrogen (N2), which may have small amounts of [0233] Due to the increased solubility of 02 and reduction residual 02, are susceptible to the formation of metmyoglo- in the partial pressure of 02 required for maximal metmyo-bin due to the presence of the residual 02. If the 02 globin formation at sub-zero temperatures, maximum dis-concentration is not excessive, the meat tissue will metabo- coloration occurred several millimeters below the meat lize some of the residual 02 and any metmyoglobin formed surface. Since meat is translucent, such discoloration is will be reduced to deoxymyoglobin as a result of metmyo- normally visible.
The deeper in the tissue metmyoglobin globin reducing activity (MRA) within the muscle tissue. occurs, the lower is its visibility, and this resulted in low [0229] In packaged fresh beef, 2-4 days are required for levels of discernable discoloration and higher retail appear-reduction of metmyoglobin to deoxymyoglobin. When ance scores during retail display. Also, use of optimum 02 absorbing capacity in each retail tray prevented transient stored meat is removed from the controlled atmosphere, it discoloration of beefsteaks, which probably retained MRA
blooms to the desirable, bright red color associated with and delayed discoloration further. Prevention of such tan-freshly cut meat, but this will not occur if a substantial sient discoloration has been reported above. The combina-amount of metmyoglobin is present. The MRA of muscle tion of these hurdles resulted in reduced discoloration even tissue is limited in stability and once exhausted is not available to convert metmyoglobin back to deoxymyoglo-on day 3 of the retail display period. Since the bright-red bin, color of meat was restored, the steaks received acceptable retail appearance scores on day 3 of retail display for any [0230] To overcome this disadvantage and address the CAP storage interval, after which the meat was in an issue of transient discoloration during CAP storage of fresh unacceptable range. Thus, visual characteristics seem to be beef, the present work was undertaken to combine the the limiting factor for acceptability of steaks.
efficacies of CAP storage of fresh beef and 02 absorbent technology and demonstrate the shelf life extension of [0234] Steaks had a slight off-flavor on day 0 of retail display after 8 weeks CAP storage and onwards. Consider-retail-ready fresh beef under these conditions. Tenderloins ing the intrinsic variability in meat cuts, such slight dete-are known to have very poor color stability and discolor rioration of flavor and odor may be of no practical impor-rapidly even at very low 02 concentrations and at a storage temperature of ¨1.5 0.5 C. The effect of intermuscular tancc.
differences on color stability adds another variable that [0235] The relative success of the system used in the complicates continuous prevention of meat discoloration, present study is noteworthy considering the poor color Biochemical factors, such as oxygen consumption rate stability of PM
muscle. The system is able to deliver longer (OCR) and MRA, have been reported to be different for CAP storage with longer subsequent retail display life if beef different muscles. Therefore, the system was tested using a muscles with higher color stability are used. It can be beef muscle type that had poor color stability and repre- conservatively concluded that the present system has the seated a worst-case challenge for centralized meat opera- capability of providing a 10 week CAP storage life with a tions. subsequent 3 day retail display life for centrally prepared [0231] The performance of 02 absorbent technology was beef tenderloin steaks. Master-bags filled with 0.4% CO will also put on test during this study for its ability to prevent certainly need oxygen scavengers placed outside the meat-transient discoloration by rapidly reducing the residual 02 trays.
concentration to essentially 0 ppm, and thereby preserving the limited MRA of muscle. Retained MRA may further EXAMPLE 5 enhance retail display life of steaks. It is also true that steaks packaged with an optimum 02 absorbing capacity have more Shelf Life Extension of Lamb Chops Utilizing retail display life when compared with steaks packaged Zero-Oxygen Tech without such capacity. Thus, the system used in the present [0236] 1.
Master-Packaging, Storage, and Sampling of study was believed to have the capability to provide solu- Steaks tions for the major problems of residual 02 concentrations encountered in centralized fresh meat distribution. [0237] Fresh lamb primal cuts from animals slaughtered 24 hours previously, were obtained from a lamb abattoir.
(0232] For all CAP storage intervals, the steaks had acceptable visual, odor, and flavor scores on day 0 of retail Eighty chops of 2-cm thickness were prepared from these cuts. Each chop was placed on an absorbent pad and a foam display. Additionally, metmyoglobin content and microbial tray, with 02 scavengers having an absorption capacity of at growth were minimal and in some cases even lower than in least 10 cc (e.g. 10 mL) per pound placed underneath the fresh controls on the day packs were opened and displayed.
Along with a low storage temperature of ¨1.5 0.5 C., an absorbent pad.
Each retail tray was over-wrapped with a shrinkable 02 permeable film with an 02 transmission rate of important factor influencing microbial content was low 8000 mL per m2 per 24 hours at 23 C., 70% relative initial microbial load. Beef tenderloins were used in the humidity, and atmospheric pressure. After sealing, the film study, and these muscles are internally located and do not undergo much handling by meat-cutters as compared to was shrunk to the tray using a hot-air gun. One 3-mm hole was made at the opposite corners of the tray. Four such retail other cuts. This protects them to some extent from cross-contamination, and hence yields low initial microbial load, trays were placed in per 24 hours at 23 C., 70% relative a master pack with 02 transmission-rate The meat cuts used in the present study had very low initial m2of 0.55 mL
per microbial numbers, which would have delayed onset of humidity, and atmospheric pressure. Master bags containing spoilage levels of microorganisms, and thus may have 02 scavengers outside the meat trays and inside the master reduced the occurrence of off-odors. It was not surprising bag were also prepared.
that microbial growth and odor did not limit CAP storage [0238] The bags were evacuated, filled with 4.5 L of N2 and retail display life of steaks. and sealed using a CAP machine. Ten such bags were US 2006/0228449 Al Oct.
12, 2006 prepared. Similarly, ten such packages were prepared by [0246] 5. Flavor Assessment of Master-Packaged Lamb using plastic trays instead of foam trays. During initial Chops packaging, the 02 concentration was measured in every fifth [0247] The lamb chops were cooked the lamb chops after bag by using an 02 analyzer (Mocon MS-750, Modern 27 and 55 days of storage for flavor assessment.
Controls Inc., Minneapolis, Minn.), which uses a solid state 02 ion conduction material, zirconium oxide. The 02 ana- [0248] 6.
Microbial Assessment lyzer had an accuracy of t5 ppm in the 0 ppm to 1000-ppm [0249] Analysis of the lamb chops, after every weekly range, 0.05% in the 0.1% to 10% range, and t0.1% in the storage interval, for aerobic, anaerobic, E. colt, Listeria, and

10% to 100% ranges for 02 concentrations. The resolution Salmonella was performed.
of the analyzer was smaller than the accuracy; that is, in the Results 0 to 1000 ppm 02 concentration range the resolution was 1 ppm. [0250] a. Oxygen Concentration [0239] The master packs were stored at -1.5 C. Two [0251] The oxygen concentrations in the master packages master packs (one containing foam trays and the other were in the range of 0.5% immediately after packaging containing plastic trays) were opened at subsequent 1 week which went up to 2-5% within a few minutes of gas flushing storage intervals for 8 weeks. The 02 concentration in each and sealing.
The oxygen concentration was reported to be 0 bag was measured immediately before opening the bag. for each weekly storage interval.
Master bags containing meat cuts and oxygen scavengers having oxygen absorbing capacity of at least 10 cc per pound [0252] b.
Visual, Odor, Microbial and Flavor Assessment of meats, placed only outside the meat-trays, were also [0253] The lamb chops had bright red to dark red color, prepared. The over-wrap film of the meat-trays had at least zero to minimal discoloration, extremely acceptable appear-one hole of less than 5 mm diameter. Such master-bags were ance, and no off-odor for all the storage and display time flushed-back with a gas-mixture containing 64.6% Nitrogen, intervals.
(FIGS. 5C1-5J) The microbial load showed a 0.4% CO, and 35% CO2. gradual increase in the count, with no detrimental effect to the meat quality. Also, pathogen-growths were negative for [0240] 2. Display and Sampling of Retail Trays all storage intervals. (FIGS. 5A-58) The flavor was assessed [0241] Upon removal from primary CAP storage at to be extremely acceptable after 27 days of storage.
weekly intervals, and on day 0 of retail display, master [0254] c.
Discussion packaging was removed and each group of 8 retail trays was placed for sensory analysis. The displayed chops were [0255] The lamb chops were extremely desirable for all examined for color, discoloration, retail-acceptability, off storage intervals and display periods. The testing showed no odor intensity, odor acceptability, and odor description, 20 difference between chops packaged in plastic and foam trays min after opening of the master-packages. After visual and with all having retail acceptability and no odor throughout odor scores were obtained, two chops (one from each master the display period. (FIGS. 5C-I-5J) No substantial difference bag) were removed from the display case, and samples were in desirability was reported for lamb cuts in the master bags taken for microbial analysis. A similar procedure was with 02 scavengers in meat trays or in master bags with 02 repeated for all storage intervals, scavengers placed only outside the meat trays; i.e. in the mater bags. It is believed this is due to preventing the [0242] 3. Visual Assessment of Master-Packaged Lamb metmyog,lobin reducing activity of the muscle by absorbing Chops the oxygen rapidly to zero levels. This enhances the display life of centrally prepared retail ready meat cuts. In addition, [0243] A three-four-member panel was used for the sub- a nitrogen atmosphere provides an anaerobic atmosphere, jective evaluation of the steaks. Color scores were assessed and helps in reblooming of the meat once removed from the using an eight point descriptive scale: 0-Completely discol- master package. When opened, meat-cuts in master bags ored, 1-White, 2-Pale pink, 3-Pink, 4-Pale red, 5-Bright containing 0.4% CO
bloomed quickly when compared with cherry red, 6-Slightly dark red, 7-Moderately dark red, meat-cuts in master-bags containing 100% nitrogen. Master 8-Extremely dark red. Surface discoloration was evaluated bags filled with 0.4% CO will certainly need oxygen scav-using a seven point descriptive scale: 1=0% (none), 2=1- engers placed outside the meat-trays.
10%, 3=11-25%, 4=26-50%, 5=51-75%, 6=76-99%, 7=100%. Retail appearance was assessed on a seven point [0256] The zero oxygen packaging system for centralized hedonic scale: 1=Extremely undesirable, 2-Undesirable, meat operations extends the available display and storage 3-Slightly undesirable, 4-Neither desirable nor undesirable, times for the meat. A storage life of 8+ weeks with a 5-Slightly desirable, 6-Desirable, 7=Extremely desirable. subsequent display life of 4+ days was obtained for centrally prepared retail ready lamb chops by employing zero oxygen [0244] 4. Odor Assessments of Master-Packaged Lamb storage.
Chops [0245] A three to four-member panel was used for the odor assessment. Off odor intensity scores were assessed using a Shelf Life Extension of Pork Chops by F,mploying four point descriptive scale: 1-No off odor, 2-Slight off odor, 3-Moderate off odor, 4-Prevalent off odor; odor "Zero Oxygen Packaging System"
acceptability scores were assessed using a five-point scale: [0257] 1.
Master Packaging, Storing, and Sampling of 1-Acceptable, 2-Slightly acceptable, 3-Neither acceptable Pork Chops nor unacceptable, 4-Slightly unacceptable, 5-Unaccept-able; and off odor description scores were assessed using a [0258] Fresh pork loins from animals slaughtered 24 hours six-point scale: 1-Sour-sulfur (rotten eggs), 2-Sour-lactic previously, were obtained from a local beef abattoir. One acid, 3-Putrid, 4-Dirty socks, 5-Floral/Fruity, 6=Other, hundred and twenty chops of 2 cm thickness, were prepared US 2006/0228449 Al Oct.
12, 2006 from these porkloins. Each pork chop was placed on a 3-11-25%, 4-26-50%, 5-51-75%, 6.76-99%, 7.100%.
152x114 rum absorbent pad in a 216x133x25 mm (LxWxH) Retail appearance was assessed on a seven-point hedonic solid polystyrene tray with 02 scavengers of 02 absorption scale: I-Extremely undesirable, 2-Undesirable, 3-Slightly capacity of at least 10 mL per pound of meat placed undesirable, 4-Neither desirable nor undesirable, 5-Slightly underneath the chop. Master bags where 02 scavengers were desirable, 6-Desirable, 7-Extremely desirable.
placed only outside the meat trays were also prepared. Each retail tray was over-wrapped with a shrinkable 02 permeable [0265] 4. Odor Assessments of Master-Packaged Chops film with an 02 transmission rate of 800 mL/m2 per 24 hours [0266] A five-member panel was used for the odor assess-at 23 C., 70% relative humidity, and atmospheric pressure. meat. Off odor intensity scores were assessed using a After sealing, the film was shrunk to the tray using a hot-air four-point descriptive scale: 1-No off odor, 2-Slight off gun. Then, two 3-mm holes were made at the opposite odor, 3-Moderate off odor, 4-Prevalent off odor, odor corners of the tray to allow free exchange of atmospheres acceptability scores were assessed using a five-point scale:
during gas flushing. Four such retail trays were placed in an 1-Acceptable, 2-Slightly acceptable, 3-Neither acceptable EVA co-extruded master pack with 02 transmission-rate of nor unacceptable, 4-Slightly unacceptable, 5-Unaccept-0.55 mL/m2 per 24 hours at 23 C., 70% relative humidity, able; and off odor description scores were assessed using a and atmospheric pressure. The bags were evacuated, filled six-point scale:
1-Sour-sulfur (rotten eggs), 2-Sour-lactic with 4.5 L of Is12, and sealed using a CAP machine. Thirty acid, 3-Putrid, 4-Dirty socks, 5-Floral/Fruity, 6-other.
such bags were prepared. An additional 8 retail trays were prepared and treated as un-stored controls. [0267] 5. Microbial Analysis [0259] The master packs were stored at -1.5 0.5 c On [0268] A 10 cm2 sample was obtained at each sampling week 0 and day 0 of retail display, four steaks in retail trays, time (on day 0 and 4 of each storage interval) from each of serving as fresh, un-stored controls, were analyzed for the two chops using a sterile cork borer. Then, the sample visual, odor, taste, and microbial characteristics. The visual was placed into a stomacher bag with 10 ml. of 0.1%
analysis was done daily for 6 days. On day 6 of retail display, peptone solution and was massaged for 120 seconds using a odor, taste, and microbial analyses were done in addition to commercial stomacher, yielding a dilution of 10 . The visual examination. Two master packs were opened at homogenate was further diluted 10-, 100-, 1000-, 10000-, subsequent 1 week storage intervals for 15 weeks. The 02 and 100,000-fold, after which 0.1 nil, volumes of undiluted concentration in each bag was measured immediately before homogenate and of each dilution were prepared and the opening the bag. Master bags containing meat cuts and spread on duplicate plates of APT. The plates were incubated oxygen scavengers having oxygen absorbing capacity of at aerobically for 3 days at 25 C. The micro flora was least 10 cc per pound of meats, placed only outside the determined from plates bearing 20-200 colonies. (FIG. 6F) meat-trays, were also prepared. The over-wrap film of the Results meat-trays had at least one hole of less than 5 mm diameter.
Such master-bags were flushed-back with a gas-mixture [0269] a. Measurement of 02 Concentration containing 64.6% Nitrogen, 0.4% CO, and 35% CO2.
[0270] The 02 concentration was 5% at initial packaging, [0260] 2. Display and Sampling of Retail Trays and after a CAP storage interval it was reduced to 0 ppm.
The oxygen concentration was down to 0 ppm within three [0261] Upon removal from primary CAP stroage at hours of master pack closure.
weekly intervals, and on day 0 of retail display, master packaging was removed and each group of 8 retail trays was [0271] b.
Evaluation of Chops placed in the center of the display shelf. The displayed pork chops were examined for color, discoloration, retail-accept- [0272] A
storage life of at least 15 weeks and a retail ability, off odor intensity, odor acceptability, and odor display life of at least six days for pork chops packaged by description, 45 min after opening of the master-packages. employing "zero oxygen packaging systems approach" were obtained. (FIGS. 6A-6F) When opened, meat-cuts in mas-[0262] After visual scores were obtained, two chops (one ter-bags containing 0.4% CO bloomed quickly when corn-from each master bag) were removed from the display case, pared with meat-cuts in master-bags containing 100% nitro-and samples were taken for microbial analysis. The remain- gen. Master bags filled with 0.4% CO will certainly need ing six chops were left in the display case, and were oxygen scavengers placed outside the meat-trays.
examined for visual characteristics at subsequent intervals of 24 hours and reflectance spectra at 12 hours for 96 hours. [0273] It is interesting to note that the visual and microbial After 144 hours of retail display, the chops were analyzed in characteristics of the pork chops remained in an acceptable a similar fashion as on day 0 of retail display. During sensory condition even after such a long storage in cooler and at evaluation, the samples remained in the display case and the retail display case.
well-trained panelists made judgments independently. A
similar procedure was repeated for all storage intervals. DEMONSTRATED
PRINCIPLES
[0263] 3. Visual Assessment of Master-Packaged Chops [0274] 1. Metmyoglobin reducing activity is capable of being restored provided the oxygen concentration in the [0264] A five-member panel was used for the subjective master package which contains meat cuts is reduced to zero evaluation of the steaks. Color scores were assessed using an ppm within a few hours of sealing the package.
five-point descriptive scale: 0-Completely discolored, 1-Extremely pale, 2-Pale, 3-Normal, 4-Dark, 5-Ex- [0275] 2. Oxygen absorption kinetics by an oxygen scav-tremely dark. Surface discoloration was evaluated using a eager is bi-phasic where the rate of oxygen absorption varies seven-point descriptive scale: 1.0% (none), 2-1-10%, with the initial oxygen concentration.

US 2006/0228449 Al Oct.
12, 2006 [0276] 3. Pre-treating the oxygen scavengers by moisture 02 scavengers must also self-activate in the presence of 02 causes faster activation, at a >60% relative humidity (caused by the fresh meat cuts).
[0277] 4. Oxygen scavengers based on an iron chemical [0286] Besides the half-life of residual 02 concentration in system can be effectively utilized to reduce the oxygen the bag. an important consideration is the type of meat cuts.
concentration in the master bag. Beef and lamb/veal muscles, especially tender loins, have very poor color-stability, and metmyoglobin formation, with [0278] 5. The oxygen half-life will be dependent upon the the concurrent discoloration, has the highest rate for these initial oxygen concentration in the package and the ambient muscle-types.
Hence, a very fast oxygen scavengers temperature. (capable of working at 0-4 C.) with an optimal capacity of [0279] 6. The permeability of packaging films having very 10-1000 cc (e.g.
10-1000 mL) per pound of meat (depending high oxygen ingress rate is significantly reduced at sub-zero upon the location of meat muscle, i.e., loins, ribs, etc.) is desired in a master bag with residual oxygen concentration temperatures where the films act as an oxygen barrier.
of less than 5%. Also, placement of the 02 scavengers should [0280] Included within the scope of the present invention be close to the meat cuts to avoid any discoloration due to and the abovementioned examples are compositions corn- oxygen-entrapment.
prising various combinations of these substances and mate-rials. Aspects of the present invention have been described color stability. Fast oxygen scavengers (capable of working by way of example only and it should be appreciated that at 0-4 C.) with an optimal capacity of 10-500 cc (e.g.
modifications and additions may be made thereto without departing from the scope thereof. 10-500 mL) per pound of meat cut is desired in a master-bag with residual oxygen concentration of less than 5%. For pork INDUSTRIAL APPLICABILITY products, oxygen scavengers can be placed outside the meat-trays within the master bag. For other meats (e.g. beef, [0281] The present invention finds specific industrial lamb, and veal), the oxygen scavengers can either be inside applicability in the meat distribution and retail industries, the meat trays, or inside the master bag and outside the meat The automated machine disclosed herein used to package trays, depending on the muscle type. In either case, oxygen meat cuts achieves zero oxygen packaging in a central Permeability of the meat trays must be sufficient for residual packaging facility for master bag storage and retail display. trapped oxygen to diffuse out of the meat trays.
The storage and display times are significantly increased [0288] The primary consideration is to have fast-type using the system. oxygen scavengers with the capability to reduce oxygen [0282] FIG. 7 shows the basic steps employed in the concentrations to 0 ppm (zero oxygen level) within 24 hours invention organized in to four separate procedures or pro- of packaging closure. Optimal oxygen scavenging capacity cesses. Steps 705-715 comprise the first procedure of deter- is between 10 cc to 1000 cc (e.g. 10 mL to 1000 mL) per mining the capacity of the 02 scavenger to use. Step 720 pound of meat-cuts in a master-bag having residual oxygen comprises the second procedure of determining placement concentration of less than 5% and resulting in a half-life for of the 02 scavenger. Steps 725-735 is the third procedure of oxygen ranging from 0.6 to 2 hours.
packaging, and steps 740-750 are the fourth procedure of [0289] The desired oxygen scavengers is chemical-based, storage and display of the meat. because enzyme-based scavengers have been shown to have [0283] For determining the half-life process, in step 705, low oxygen absorption rates as shown in the data presented in this and the earlier Ser. No. 10/434,010 application. Iron the master bag is selected and prepared. The master bag must chemical systems, from the chemical group of ferrous and exhibit low oxygen transmission-rates, preferably <10 cc/m2/day at 23 C. Typically, this will require a master bag ferric ions, are the preferred oxygen scavenging materials.
composed of high oxygen barriers films such EVOH or foil, However, other chemical groups such as magnesium and and the master bag must have good seal-strength. copper can be used. The material used is finely granulated to a powdered form and its capacity is determined by the [0284] The oxygen permeability of the bag must also be amount of powdered material placed inside a sachet. The established. A master bag is filled with the appropriate preferred composition of the scavenger material follows:
quantity of 100% nitrogen (or any other inert gas) or a combination of >50% nitrogen (or other inert gas) plus other[0290] iron (<25%, preferred range 15-20%) non-inert gases (e.g. CO, and/or CO or other gases) and then [0291] carbon (<35%, preferred range 20-25%) the residual 02 level in the bag is measured immediately [0292] vermiculite (<20%, preferred range 10-15%) after sealing, three hours after sealing, and 24 hours after sealing using different sampling sets of bags for each men- [0293]
dcionized water (<10%, preferably 5%) surement.
[0294] salt (preferably NaCI, <10%, preferably 5%) [0285] In step 710, residual 02 concentration in the bag is [0295] The desired capacity of oxygen scavengers used taken into consideration and an appropriate Arrhenius equa-tion is used to calculate the half-life of oxygen in the master ranges from 10 cc to 1000 cc per pound of meat packaged in a master bag. The exact capacity and half-life is calculated bag, and an appropriate 02 scavenger with an optimum capacity is designed or selected. In step 715, the 02 scav- based on the Arrhenius equation found in patent application Ser. No. 10/434,010. The scavengers need to function in the eager is chosen. The scavenger chosen must have sufficient capacity (10 cc-1000 cc) to rapidly absorb the 02 to the temperature range of ¨2.222 to 7.222 C. (28 to 40 F.).
required low level and achieve a zero oxygen storage [0296] For the next procedure of determining placement of atmosphere within 24 hours of sealing the master bag. The the 02 scavenger, in step 720 placement of the 02 scavenger US 2006/0228449 Al Oct.
12, 2006 depends primarily on the meat type. Depending on the can be constructed from any acceptable, standard material meat-type. the 02 scavenger can be placed inside the meat- commonly used for meat trays, preferably styrofoam. The tray or outside the meat-tray in the master bag. For beef and over-wrap 710 likewise can be made from any conventional lamb cuts, placing the 02 scavenger inside is usually con- oxygen permeable plastic wrapping film. In this embodi-sidered optimal. However, 02 scavengers can be placed ment, the meat 715 is placed on top of and in direct contact with the oxygen scavenger sachet, with an absorbent pad outside the meat-trays provided one or more pin-holes are 725 placed underneath the oxygen scavenger. FIG. 9 shows made in the over-wrapping film surrounding the meat-tray, another embodiment. The meat tray 805 is covered by the each hole having a diameter of less than 5 mm. It is important for the film over-wrapping to allow exchange and plastic over-wrap 810. However, in this embodiment the meat 815 is placed on top of and in direct contact with the diffusion of atmosphere, or more specifically oxygen, absorbent pad 820. The oxygen scavenger sachet 825 is between the interior and exterior of the meat tray when placed underneath the absorbent pad 820. For both of these sealed in the master bag. embodiments, oxygen scavenger sachets used attain enough [0297] For the third procedure of packaging the meat, in absorption capacity to achieve an 02 half-life of between 0.6 step 725 between 0.5-4.0 lbs of meat are placed on appro. to 2.0 hours. It is preferred that the oxygen absorption ptiate trays. Conventional foam trays can be used in the capacity be at least 10 mL per pound of meat and attain a packaging. Tests performed using foam and plastic trays, zero oxygen storage atmosphere within 24 hours of pack-both over-wrapped and lidded, showed no substantial dif- aging.
ference.
[0302] FIG. 10 shows an embodiment for a master bag [0298] In step 730, the meat trays are over-wrapped for containing meat trays with the oxygen scavengers only eventual display in a meat case. The over-wrapping film found inside the meat trays sealed in the master bag. The must have high oxygen transmission rates on the order of master bag 905 will contain one or more meat trays 910. The >8000 cc/m2/24 hours at 23 C. At least one pin-hole of <5 atmosphere within the master bag 905 is flushed of oxygen mm diameter must be made on the over-wrapping film that and injected with a non-oxygen gas consisting primarily of wraps the meat-trays to prevent oxygen entrapment inside 100% nitrogen or a nitrogen-rich (>50% nitrogen) gas the meat-trays or allow diffusion out of oxygen entrapped mixture before sealing. FIG. 11 shows an embodiment of a within the meat-trays (e.g. depending on whether the 02 master bag containing a cut of primal or sub-primal meat.
scavengers are located inside the tray or the mater bag). The [0303] 02 scavengers placed inside the master bag, typi-pin-holes are required because despite the permeability of cally possess 02 absorbing capacity of 10 cc/lb (e.g. _410 the film, the film still acts as an oxygen-barrier, and oxygen mL/lb) of meat. In this embodiment, the master bag 1005 molecules become entrapped within the meat-tray causing contains cuts of unwrapped primal or sub-primal meat 1010.
discoloration to the meat. However, for pork, the pin-holes The master bag 1005 is flushed of oxygen and injected with can be eliminated. This diffusion action permits trapped a non-oxygen gas consisting primarily of 100% nitrogen (or oxygen to defuse outside the tray and be absorbed by oxygen any other inert gas) or a combination of >50% nitrogen (or scavengers outside the tray, or conversely for residual oxy-other inert gas) plus other non-inert gases (e.g. CO, and/or gen trapped in a master bag lacking oxygen scavengers to diffuse into a tray for absorption by scavengers within a meat CO or other gases) before sealing.
tray. [0304] Oxygen scavenger sachets 1015 with appropriate [0299] In step 735, single or multiple meat trays are placed capacity are added to the master bag 1005 before sealing into a master bag, which will include an 02 scavenger of having a total oxygen absorbing capacity of -.10 mL per appropriate 02 absorbing capacity. The master bag is gas- pound of meat to achieve an 02 half-life of between 0.6 to flushed (single or multiple flushings either with or without a 2.0 hours.
FIG. 12 shows another embodiment where meat vacuum to aid removing oxygenated air) using either 100% trays and oxygen scavengers are sealed in a master bag. The N2 or >50 N2 and the balance with CO, CO2 and other trace master bag 1105 contains a plurality of meat trays 1110.
amounts of non-oxygen gases (e.g. He, H2, H20, etc) to Oxygen scavenger sachets 1115 are included inside the achieve a residual 02 concentration of less than 5% inside master bag 1105 before the master bag 1105 is flushed, the master bag. The N2 atmospheric content preferably injected with the desired gas mixture, (100% nitrogen, ranges between 56%400%. A small percentage of CO nitrogen-rich (>50%
nitrogen) with balance of CO2 and (<5%) will aid in retaining color of the meat. The preferred CO), and then sealed.
CO content ranges between 0.1 % to 5%. After the desired [0305] The invention also includes the apparatus used for gas mixture is injected into the bag, it is sealed and the packaging the master bags. The apparatus consists of hori-oxygen scavengers, both inside and outside the trays, absorb -zontal-form-fill-seal equipment designed to provide an inte-any residual oxygen. grated packaging system for retail-ready meat cuts in meat [0300] The fourth procedure includes steps required for trays or primal or sub-primal meat cuts of the appropriate storage and distribution for display. In step 740, the master size. The preferred maximum size of product packaged by bags are placed in storage under temperatures in the range of the machine is 28 inches long, 18 inches wide, and 6 inches 0 to -2.22 C. (e.g. 32 -28 F.). In step 745, the meat is high. The equipment should be constructed of stainless steel distributed to appropriate grocers or grocer distribution to facilitate cleaning. FIG. 13 shows a basic schematic of the centers with storage maintained under 40 F. Meat can be Packaging system using the machine.
maintained in this storage and distribution packaging for up [0306] In the machine schematic of FIG. 13, meat trays to 15 weeks depending on the type of meat. In step 750, the 1205 of the preferred maximum size are fed into the appa-meat is removed from the master bags and placed in meat ratus using a conveyor system 1207 powered by a servo displays at the appropriate grocer under temperature condi-motor that moves tions >0 C., typically for up to nine days. the meat trays 1205 through the apparatus.
For most meat packaging applications, the appropriate oxy-[0301] FIG. 8 shows the arrangements of the elements of gen scavenger sachets 1210 will be placed inside the meat a meat tray for one embodiment for a meat tray. The tray 705 tray and outside the meat tray inside the master bag, but for US 2006/0228449 Al Oct.
12, 2006 some chosen applications other placement configurations will provide all the nitrogen for the system, and this nitrogen may be used (e.g. scavengers in meat tray only, scavengers gas flow may be in a gaseous or liquid state, preferably outside meat tray only, or no scavengers). A pin-hole of g 5 gaseous as cryogenic temperatures of liquid nitrogen can be mm should be punched in the over-wrap of the meat tray, or problematic and would needlessly complicate the system multiple holes to facilitate diffusion of trapped oxygen from without any real benefit. The other gas line will supply the the retail meat trays.
mixture of other gases chosen by the user of the system (CO2, CO, etc).
[0307] The meat trays 1205 enter a folding box 1211 which constructs the master bags. One or more 1205 meat [0310] Alternatively, each gas type may use its own gas trays enter the folding box 1211, which is supplied with the supply line, but it is contemplated that the gas feed for the master bag material by a film pulley system 1212 supplying other gases will be in a gaseous state and a safety valve 1223 bag film material 1214 from a continuous sheet of material is provided on this gas supply line 1224 for venting in the wrapped onto a roller system 1213. The folding box 1211 even that the pressure rises to an unsafe level inside the tank folds the fed master bag film material 1214 around the meat 1220.
The preferable gas mixture for most meat packaging trays 1205 to form the master bag by heat-sealing the edges will be composed of >50 N2 and <5% CO and the balance together to form a master bag. Alternatively, the continuous of the mixture CO,. A safety system may be required for sheet roller system 1213 may consist of a number of monitoring with these gas mixtures containing CO and CO2, prefabricated master bags coupled together by perforations which can be dangerous at relative low concentrations (e.g.
so as to be easily separated and opened by the folding box over 50 ppm for CO gas and over 5,000 ppm for CO2).
1211.
[0311] The sides of the master bag are heat-sealed before [0308] As the forming master bag passes through the gas flushing and the ends of the master bag are heat-sealed folding box, a wrapper pre-heating mechanism 1215 heats by a cross-reciprocating seal mechanism utilizing a specific the material to help shrink it onto the meat trays 1205, before dwell time, speed, pressure, and temperature. A servo motor reaching a set of propelling and sealing rollers 1216 that seal controls the cross reciprocating seal. The parameters (speed the end of the master bag. During this process, between the of the conveyor and cross-sealing speed) depend on the size mechanisms of 1215 and 1216, simultaneously with the of the master bag. All of the functional components such as formation of the master bag, gas flushing is performed to the servo motor, conveyor speed, cross-sealing speed, gas evacuate air out of the master bag while the desired gas mixture control, bag sizing, and other similar functions, are mixture is injected. The gas flushing can include applying a preferably controlled by a Pentium-based computer control vacuum to the master bag to help evacuate ambient air from system operated by a windows style touch screen. At the end the master bag. of the process, a master bag 1226 containing meat trays or primal cuts of meat is produced containing a desired gas [0309] The gas mixture is supplied from a gas supply tank 1220 containing pre-mixed gases supported above the con-mixture reduced to zero oxygen content for long-term stor-a of the meat cuts.
veyor system by a support rack 1217, or the gas can be ge supplied from multiple tanks, or gas lines leading to an [0312] While the invention has been particularly shown exterior tank of pre-mixed gases. Gas is supplied through a and described with respect to preferred embodiments, it will gas supply line 1218, with gas flow regulated by a solenoid be readily understood that minor changes in the details of the valve 1219. The gas tank includes warning devices 1221 that invention may be made without departing from the spirit of can include pressure, temperature, and composition sensors, the invention. Having described the invention, It is contemplated that two gas supplies lines will flow into the tank. A nitrogen gas line 1222 will supply pure N, to the EXAMPLE I
gas tank, and may include a bypass to feed directly into the gas supply line 1218 into the apparatus. The N2 supply line [0313]
TABLE lA
Half-life of 02 in bags containing scavengers based upon enzymes and iron chemical systems, and air or N, atmosphere.
0, half-life (h) Scavenger-type Atmosphere 25 C. 12 C. 2 C. -1.5 C.
Iron chemical system Air 0.6 (0.04)* 0.7 (0.02) 1.0 (0.03) 2.5 (0.04) (type 1) N2 air 1.3 (0.03) 1.5 (0.04) 2.2 (0.05) 2.3 (0.05) Enzyme system (type 1) Air 1.0 (0.03) 1.6 (0.02) 4.0 (0.02) 7.1 (0.04) N2 4- air 3.3 (0.02) 7.1 (0.03) 12.0 (0.03) 8.4 (0.03) Iron chemical system Air 0.6 (0.04) 0.8 ((P.05) 0.8 (0.04) (type 2) N2 + air 0.9 (0.02) 0.9 (0.04) 1.3 (0.04) Enzyme system (type 2) Air 1.6 (0.02) N2 + air 6.5 (0.06) Iron chemical system Air 4.5 (0.08) (tY0e 1 in over-wrapped N2 + air 5.0 (0.08) tray) Standard deviation.
- An experiment was not performed under this condition.

US 2006/0228449 Al Oct.
12, 2006 [0314]
TABLE IB
Constants of first order kinetics equation for different scavengers.
Constants of first order Calculated Temp. Initial 02 kinetics equation 02 half-Correlation Scavenger-type (` C.) Atmosphere concentration (ppm) k (11-') Ao life' (h) coefficient (r2) Iron chemical system 25 Air 200,000 2.46 3.94 0.3 0.98 (type 1) 25 N, + air 500 0.35 0.51 1.8 0.92 12 Air 200,000 1.82 396 0.4 0.96 12 N2 + air 500 0.36 0.61 1.9 0.98 2 Air 200,000 0.69 3.61 1.0 0.99 2 N2 -e= air 500 0.25 0.79 2.7 0.99 -1.5 Air 200,000 0.31 3.54 2.3 0.92 -1.5 112 + air 500 0.26 0.76 2.7 0.99 Enzyme (type 1) 25 Air 200,000 0.56 3.34 1.2 0.99 25 N2 + air 500 0.20 0.88 3.5 0.99 12 Air 200,000 0.40 3.62 1.7 0.99 12 N2 + air 500 0.09 0.84 7.7 0.99 2 Air 200,000 0.20 3.45 3.5 0.99 2 N2 + air 500 0.06 0.80 11.5 0.96 -1.5 Air 200,000 0.08 3.72 8.7 0.98 -1.5 N2 + air 500 0.08 0.84 8.7 0.99 'I n10210 . -kt + Ao . -kt + In[02L; [Oz]t is voltune (tilL) of 02 in the pack atmosphere at time t (hour) and 1021,, is volume (mL) of 02 in the pack atmosphexe at t . 0 h.
bCalculated half-life (h) . 0.693/k: observed half-life in Table 1.
(2) indicates text missing or illegible when filed EXAMPLE 2 [0316]
[0315] TABLE 2b TABLE 2a Oxygen (02) concentration in master packs containing beef and pork stored at r C. in 100% nitrogen (N,) atmosphere for seven days.
Description of treatments for beef steaks and pork chops for experiment I. 02 Concentration (ppm) Treatment N' Description Treatment Beef Pork A 3 Lidded control tray with meat B 3 Lidded tray containing meat and grid During initial packaging C 3 Lidded tray with meat and absorbent pad A 214 D 3 Lidded tray containing meat and 02 scavengers inside the B 334 retail tray C 890 862 E 3 Lidded tray containing meat, grid, and absorbent pad D' 0 F 3 Lidded tray containing meat, grid. and 02 scavengers E 201 inside the retail tray F* 0 0 0 3 Lidded tray containing meat, absorbent pad, and 02 G" 30 0 scavengers inside the retail tray /V 1560 0 H 3 Lidded tray with meat, grid, absorbent pad, and 02 D 1 x scavengers inside the retail tray Fix 0 0 DI 3 Treatment D with 02 scavengers outside the retail tray GI x Fl 3 Treatment F with 02 scavengers outside the retail tray H I x GI 3 Treatment G with 02 scavengers outside the retail tray III 3 Treatment II with 02 scavengers outside the retail tray `02 scavengers inside the retail tray 'Number of retail trays in a master pack. x02 scavengers outside the retail tray US 2006/0228449 Al Oct. 12, 2006 [0317]
TABLE 2c Mean colour, surface discoloration, and retail appearance scores and standard errors for pork chops and beef steaks after various treatments.
Beef Pork Dis- Retail Dis Retail Treatment Colort" SE" coloration"' SE Appearance:" SE Color"
SE" coloration" SE Appearance:" SE
A 6.75" 0.22 5.58" 0.69 2.001 0.42 2.75 0.22 3.83" 0.74 3.67E 0.75 B 5.50n,c 026 5.50" 0.40 1.92E 0.45 2.75 0.22 3.33" 0.68 4.58 0.72 c 5.00D=c 0.00 5.17" 0.20 2.25E 0.44 3.00B'c 0.00 1.25c 0.22 6.75" 0.22 D**" 5/20D=c 0.20 1.00E 0.00 6.25" 0.22 3.00B=c 000 1.00c 0.00 6.75" 0.22 E 5.75E 0.25 4.67B 0.39 I.92E 0.34 3.25" 0.22 1.00c 0.00 6.50" 1126 F*** 0.09 1.67Ds 0.39 6.25" 0.44 3.08"s 0.15 1.175 0.20 6.60"s 0.26 G+++ 5.00D'c 0.30 1.830"E 0.56 4.75c 0.57 2.830,c 0.20 1.42c 0.25 6.33B 0.25 H.... 6.00" 0.06 3.50' 0.45 3.25 0.38 3.00B.c 0.00 1.17c 0.20 6.83" 0.20 D1* 5.58"J3 0.10 1.81 X 0.62 5.003A=c 0.62 2.36E 0.26 247B 0.94 5.23' 0.26 F1' 0.32 1.92D 0.86 5.00c 0.58 3.00.c 0.00 1.00c 0.00 7.00" 0.00 01" 5.58D 0.29 583" 0.47 1.835 0.36 3.00E4c 0.00 1.08c 0.15 6.92" 0.15 HI" 5.679.c 0.25 1.5 ADS 0.34 5.75" 0.38 3.00Iµc 0.00 1.08c (1.15 6.92" 0.15 'Color scale (pork chop): 0- Completely discolored, 1 = Extremely pale, 2 =
Pale, 3 = Normal, 4- Dark, 5 - Extremely dark; Color scale (beef steak):
0 - Completely discolored, 1 - White, 2 - Pale pink, 3 - Pink, 4 . Pale red, 5 - Bright cherry red, 6 - Slightly dark red, 7 - Moderately dark red, 8 -Extremely dark red.
"Discoloration scale (pork chop or beef steak): 1 - 0% (none), 2- 1-10%, 3 ..

11-25%, 4 - 26-50%, 5 - 51-75%, 6- 76-99%, 7- 100% (com-plete).
:Retail appearance scale (pork chop or beef steak): 1 - Extremely undesirable, 2 - Undesirable, 3 - Slightly undesirable, 4 - Neither desirable nor undesirable, 5 .. Slightly desirable. 6 - Desirable, 7 - Extremely desirable.
*Means in the same colunm bearing a common letter do not differ significantly (p > 0.05).
**Standard errors of difference.
'''02 scavengers inside the retail tray.
µ02scavengers outside the retail tray.
[0318]
TABLE 2d Mean values of the chemical states of myoglobin (% met-, % dcoxy-, and % oxy-myoglobin) and standard errors of difference for pork chops and beef steaks after various treatments. =
Pork Beef % of chemical states of myoglobin % of chemical states of myoglobin Treatment % met-' SE" % deoxy--= SE % oxy-t." SE % met SE %
deoxy SE % oxy SE
A 26.81A 5.80 24.180.0 5.07 49.01F-t 0.72 57.43' 6.07 0.00E 0.00 42.570x 6.07 13 20.37^ 8.80 24.6204 4.07 55.01F1)-E4 4.79 55.24"
24.16 4.12" 1.80 40.64 23.35 C 5.22B 0.94 42.10" 3.02 52.68RDs 2.16 23.2313Jµc 16.36 1.30 0.65 75.41Bsi`-c 16.93 Dm 0.019 0.01 37.77B.1/4c 3.84 62.22Bssx 3.85 058c 0.05 3.04" 1.40 96.38" 0.95

12 5.44B 2.40 47.90" 3.00 46.66r 1.70 17.7415`c 15.36 2.06D 1.58 80.200A=c 14.53 F*** 0.14B 0.10 35.343sd,c 4.35 64.52B.D.A...c 445 0.00C
0.00 1.219 1.05 98.79" 1.05 G"*" 2.07B 1.80 21.83 7.50 76.10" 8.22 2.118'c 1.82 5.67"s 2.92 92.22"-B 1.62 11"*" 000B 0.00 31.95B=DA4 338 68.053A=c 338 7.838=c 4.46 13.71A 8.80 78.46c 8.03 D1' 000B 0.00 21.07 2.35 78.93" 2.35 2.40BL 1.07 7.12'"-B 1.00 90.48As 0.15 Fl" 0.00B 0.00 28.74Bs-c 4.67 71.26"-B 4.16 2.24' 1.80 5.20" 4.45 92.56"=3 3.79 01' 0.00 0.00 25.56 -c 3.32 74.44'''" 3.32 37.29" 16.24 3.78" 1.48 58.93 S.0 17.71 HI' 6.82 5.90 27.83B-D=c 7.27 65.369'D'A'C 3.78 0.00c 0.00 8.53 A'D 4.23 91.47"J' 4.23 t% oxy- ... 100 - [(% met-) + (% deoxy-)]
*Means in the same column bearing a common letter do not differ significantly (p > 0.05).
**Standard errors of difference.
*"02 scavengers inside the retail tray.
"02 scavengers outside the retail tray.

Claims (7)

I claim: sealed inside the master bag exhibit an oxygen absorption

1. A packaging system for minimizing meat discoloration capacity sufficient to reduce the oxygen half-life within the comprising: master bag to two hours or less.
8. The packaging system for minimizing meat discolora-a stainless steel apparatus for preparing and packaging a tion of claim 1, wherein the injected gas comprises nitrogen master bag with low gas permeability containing one or as the inert gas.
more retail meat trays and including a conveyor system 9. The packaging system for minimizing meat discolora-for transporting the retail meat trays through the appa-tion of claim 1, wherein the injected gas comprises 5% or ratus, a folding box for constructing the master bag less of carbon monoxide.
from material fed from a film pulley system connected 10. The packaging system for minimizing meat discol-to a roller feed, said master bag constructed by using a oration of claim 1, wherein the injected gas comprises:
heat sealing mechanism to seal the sides of the film material forming a low gas permeable master bag; greater than 50% inert gas;
a gas injected into the master bag from a gas supply .. 5% or less carbon monoxide; and system coupled to said apparatus before sealing said master bag after oxygenated air is flushed from the bag, carbon dioxide.
said oxygenated air flushed from said bag using an 11. An apparatus for packaging meat for long-term stor-oxygen-free gas mixture comprised of at least 50% age, comprising:
inert gas to achieve an initial master bag atmosphere a conveyor system for transporting meat cuts, inside or after sealing of less than or equal to 5% residual outside of a retail meat tray, through the apparatus;
oxygen;
a film pulley feed system unrolling master bag material the retail meat tray comprising a tray with an oxygen from a roller feed system into a folding box. said scavenger sachet and an absorbent pad over wrapped folding box operating to positioning one or more meat with a gas permeable plastic-based film, said oxygen scavenger sachet containing an iron-based oxygen cuts within said master bag for packaging, said material absorbing material self-activated in an atmosphere of .. exhibiting low gas permeability to oxygen;
greater than 70% relative humidity, and said over-wrap a mechanism for flushing oxygenated air from the master film permeable to allow atmosphere exchange between bag using a gas mixture comprised of greater than or the interior and the exterior of the retail meat tray. equal to 50% inert gas and less than or equal to 5%

2. The packaging system for minimizing meat discolora- carbon monoxide to obtain an initial atmosphere con-tion of claim 1, wherein the oxygen scavenger sachet taining less than 5%
residual oxygen, said gas mixture comprises: flow into the apparatus controlled using a valve and a porous bag with an active surface area of between 4 to supplied from at least one gas supply line coupled to a 64 square inches and porosity levels ranging from 20 to storage tank:
120 gurly per second; a reciprocating seal mechanism utilizing a specified dwell chemical granules ranging from 0.001 mm to 1.5 mm in time, speed, pressure, and temperature to seal said diameter; and master bag, said master bag including oxygen scaven-gers, located inside and/or outside a meat tray, for a total weight of absorbing chemical of between 1 gram absorbing the residual oxygen in the initial atmosphere to 300 grams. to obtain a zero oxygen storage atmosphere within 24

3. The packaging system for minimizing meat discolora- hours after sealing said rnaster bag; and lion of claim 2, wherein the chemical granules comprise:
a computer control system to control speed of the con-less than 25% iron;
veyor and heat sealing speed of the master bag.
less than 35% carbon; 12. The apparatus for packaging meat for long-tenn storage of claim 11, further comprising:
less than 20% vermiculite;
a gas mixture for injecting into the master bag comprising less than 10% de-ionized water, and between 0.1% and 5% carbon monoxide, between 35%
less than 10% NaC1 salt. and 39%
carbon dioxide, and between 50% and 64.9%

4. The packaging system for minimizing meat discolora- nitrogen.
tion of claim 3, wherein the chemical granules comprise less 13. The apparatus for packaging meat for long-term than 10% zeolites. storage of claim 11, further comprising:

5. The packaging system for minimizing meat discolora-a gas mixture for injecting into the master bag comprising tion of claim 1, further comprising:
between 0.1% and 5% carbon monoxide and between one or more oxygen scavengers positioned exterior to the 50% and 99.9%
nitrogen.
retail trays within the master bag. 14. The apparatus for packaging meat for long-term

6. 'Me packaging system for minimizing meat discolora- storage of claim 11, wherein the roller feed system com-tion of claim 1, wherein all the oxygen scavenger sachets prises a plurality of firmed master bags wrapped around a sealed within the master bag obtain an absorption capacity roller connected by perforations for easy separation and of between 10 mL and 1000 mL per pound of meat. feeding into the folding box.

7. The packaging system for minimizing meat discolora- 15. The apparatus for packaging meat for long-term tion of claim 1, wherein all the oxygen scavenger sachets storage of claim 11, wherein the roller feed system cam-