WO2007134176A2

WO2007134176A2 - Antimicrobial food pad

Info

Publication number: WO2007134176A2
Application number: PCT/US2007/068682
Authority: WO
Inventors: Ivan W. Ong; Bernard Garvey
Original assignee: Microban Products Company
Priority date: 2006-05-10
Filing date: 2007-05-10
Publication date: 2007-11-22
Also published as: WO2007134176A3

Abstract

A food pad can have one or more layers, in at least one of which is incorporated an antimicrobial agent. Fluting or other textural aspect can be disposed on a surface of the food pad to minimize contact between the food pad and an object on either or both major faces thereof.

Description

ANTIMICROBIAL FOOD PAD

FIELD OF THE INVENTION

[0001] This invention relates generally to food pads, and more particularly to food pad having antimicrobial properties.

BACKGROUND OF THE INVENTION

[0002] Fruits and vegetables are commonly stored at room temperature or in a refrigerator. In the latter, food bins (i.e., crispers) are conventionally provided to facilitate moisture retention within the foods. The crisper bin is relatively isolated from the main compartment of the refrigerator, sequestering the foods and diminishing the rate at which moisture is given off by them.

[0003] While a moist environment aids in the food articles having a crisp and succulent texture, it is undesirable for fluid to pool within the crisper bin. Contact with fluids can accelerate spoilage of fruits and vegetables or negatively affect texture. One solution has been to provide a fluted or ridged topography to the bottom of the crisper bin. Fruits and vegetables thereby rest on the raised portions of the ridges, while moisture can accumulate in the hollows between ridges. One drawback to the bin fluting is that pooled fluid can serve as a bed for microbial colonization. [0004] Moreover, fluid accumulation can promote microbial colonization and/or production of unwanted odors. Additionally, fluid from the food articles can impart an odor to other foods within the remainder of the refrigerator compartment.

[0005] The produce drawer also must be cleaned regularly to remove pooled fluid and any microbial growth that has occurred.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a diagram of a first embodiment foot pad as disclosed herein.

[0007] FIG. 2 is a diagram of a second embodiment foot pad as disclosed herein.

[0008] FIG. 3 is a diagram of a third embodiment foot pad as disclosed herein.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S) [0009] The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the antimicrobial cementitious composition, its application, or uses. [0010] The terms "antimicrobial", "microbicidal", "antibacterial",

"bactericidal", "antifungal" and "fungicidal" as used herein include biostatic activity, i.e., wherein the proliferation of microbiological species is reduced or eliminated, as well as true biocidal activity wherein microbiological species are killed. Furthermore, the term "microbe" and "antimicrobial" should be interpreted to specifically encompass bacteria and fungi as well as other single-celled organisms such as mold, mildew and algae. [0011] Turning to FIG. 1 , a first embodiment food pad is a food- contacting pad 10 having an antimicrobial agent incorporated therein. In this embodiment, pad 10 preferably but not necessarily is porous to moisture. Fluid porosity facilitates collection of moisture on a surface below the food pad 10 and out of contact with foodstuffs resting thereon. [0012] One or more antimicrobial agents can be disposed in food pad 10. For example, a polymeric food pad 10 can have an organic or inorganic antimicrobial agent incorporated within the polymer. Suitable organic antimicrobial agents include, without limitation, 2,4,4'-trichloro-2'- hydroxydiphenyl ether; 2-phenylphenol; poly(hexamethylene biguanide) hydrochloride; 3,4,4'-trichlorocarbanilide; diiodomethyl p-tolylsulfone; azoles (such as propiconazoles, tebuconazoles); and isothiazolone-based compounds (such as 1 ,2-benzisothiazolin-3-one; N-butyl-1 ,2- benzisothiazolin-3-one; 2-octyl-isothiazolone; 4,5-dichloro-2-N-octyl-3(2H)- isothiazolone; methyl-3(2H)isothiazolone; and chloro-2-methyl-3(2H)- isothiazolone).

[0013] Suitable inorganic antimicrobial agents include without limitation titanium dioxide; barium monohydrate and barium metaborate(H₂0); zinc pyrithione, sodium pyrithione, and derivatives thereof; silver compounds in various forms (e.g., elemental, zeolite, amorphous glass, sol-gel formulations, and other ion-exchange formulations); copper compounds in various forms (e.g., elemental, zeolite, amorphous glass, sol- gel formulations, and other ion-exchange formulations); and zinc compounds in various forms (e.g., elemental, zeolite, amorphous glass, sol- gel formulations, and other ion-exchange formulations). [0014] The antimicrobial agent can be disposed in the polymeric material of the layer by, for example, incorporation into the polymeric matrix of the material, by post-polymerization treatment of the polymeric material, or like methods.

[0015] Suitable concentrations for the antimicrobial agent will depend on the specific agent chosen and the polymeric material used in the layer. As an example and not by way of limitation, concentrations in the range of at least about 500 ppm 2,4,4'-trichloro-2'-hydroxydiphenyl ether are expected to be efficacious in a polypropylene or polyethylene polymeric material.

[0016] Upper ends of the concentration range for any particular agent in a particular polymeric material typically are bounded by cost and bulk physical considerations, the later exemplified by negative effects to the appearance, strength, plasticity or other characteristics of the polymer. [0017] A second embodiment of the antimicrobial food pad 20, shown in FIG. 2, comprises food-contacting top layer 22 and absorbent bottom layer 24. Layers 22 and 24 can be affixed by a number of conventionally known techniques, such as glue, thermal fusion, or an intermediate layer (including, but not limited to, an adhesive layer). [0018] Top layer 22 can be constructed of a polymeric material.

Top layer 22 preferably is composed of a non-woven fibrous material, such that moisture from food resting on top layer 22 passes through top layer 22. Suitable materials for top layer 22 include without limitation a non-woven structure comprising fibers such as polypropylene, an olefin sheath over a polypropylene core, and polyethylene terephthalate (PET).

[0019] Bottom layer 24 can be a polymeric material. In this embodiment, bottom layer 24 is comprised of a fluid-absorbent polymeric material. Exemplary absorbent materials include an open-cell foam structure; and a structure having therein cotton fiber, a zeolite, a dessicant, a hygroscopic organic salt, a clay, a super-absorbent polymer, or combinations thereof.

[0020] One or more antimicrobial agents can be disposed in top layer 22 and/or bottom layer 24. Because moisture can accumulate in or adjacent bottom layer 24, it is preferable that an antimicrobial agent be disposed in bottom layer 24. Suitable antimicrobial agents include those disclosed above.

[0021] In a third embodiment, pad 30 has a top layer 32, bottom layer 34, and an intermediate layer 36 (FIG. 3). The intermediate layer 36 can be a distinct polymeric layer lending support, absorbency, or like property. Alternatively, intermediate layer 36 can be an adhesive or binder joining the top and bottom layers.

[0022] Top layer 32 again is preferably fluid-porous to permit moisture, juices, and other fluid to migrate from the foodstuffs on pad 30 to a location thereunder. Bottom layer 34 can serve to elevate pad 30 above the surface on which it rests. Bottom layer 34 alternatively or additionally can possess a fluid absorbent property, in which case intermediate layer 36 can be constructed of a fluid-porous material.

[0023] In this third embodiment, either of intermediate layer 36 and/or bottom layer 34 has one or more antimicrobial agents disposed therein. Incorporation of an antimicrobial agent in bottom layer 34 provides a microbicidal or microbistatic property thereto. It is expected that a fluid- absorbent bottom layer 34 would absorb condensation, juices and oils from foodstuffs, and other fluids accumulating in bottom layer 34. The presence of an antimicrobial agent in bottom layer 34 prevents or reduces microbial colonization in such fluids.

[0024] Similarly, one or more antimicrobial agents can be incorporated in intermediate layer 36. Disposition of absorbent bottom layer 34 distal to foodstuffs on pad 30 forces fluids exiting foodstuffs residing on top layer 32 of pad 30 to pass through intermediate layer 36. Microbes in such fluids thereby are effectively "filtered" via contact with microbicidal agent(s) in layer 36 as they pass therethrough. [0025] Bottom layer 34 of this three-layered embodiment alternatively or additionally can serve to elevate an absorbent intermediate layer 36 above the surface S upon which pad 30 rests (e.g., crisper bin floor, refrigerator shelf, countertop). Bottom layer 34 can be structured to insulate surface S from fluids and the absorbent layer(s) 34 and/or 36. Suitable non-porous materials for such a bottom layer 34 include without limitation latex, thermoplastic elastomers such as ethylene vinyl acetate (EVA), foamed polymers (e.g., EVA), and the like. Bottom layer 34 can be formed into a "texture liner" structure to aid in or maximize separation of absorbent layer 34 and/or36 and surface S.

[0026] The specific configuration of layer(s) and antimicrobial agent(s) can be selected based on the desired specifications of the finished food pad article and the microbes the pad is expected to face in a use environment.

[0027] For example, a plurality of antimicrobial agents can be disposed in the upper layer to confer greater microbicidal effect on the layer, to target different classes of microbes (e.g., bacteria and fungi, Gram- positive bacteria and Gram-negative bacteria), and the like. A first antimicrobial agent having low overall efficacy but very rapid initial microbicidal activity can be paired with a second agent having relatively slow initial activity but potent long-term action.

[0028] As another alternative, a first antimicrobial agent may be disposed in the top layer and a second antimicrobial agent, different from the first agent, in the bottom layer. Such a configuration may be chosen based on compatibility with the differing polymers in the two layers, rates or levels of activity of the agents, and so on.

[0029] In some instances, a food pad may be desired which has no antimicrobial agent in the food-contacting top layer. Antimicrobial agent(s) therefore would be disposed in a bottom layer and/or intermediate layer.

[0030] It is desirable, although not required, that an antimicrobial agent be disposed in a layer that is fluid-absorbent, as it is expected that microbes either will reside in fluid collected in use and/or that absorbed fluid would serve as a nutrient source for microbial growth. Antimicrobial agent in the absorbent layer maximizes contact between microbes and the agent.

EXAMPLE 1

[0031] An exemplary food pad was manufactured according to the second embodiment as disclosure above. [0032] The upper or top layer 22 was of a non-woven polyethylene construction formed using an acrylic latex binder. The lower or bottom layer 24 was composed of an absorbent polyether foam. The lower or bottom layer was joined to the upper or top layer via lamination. [0033] In this specific manufacture, zinc pyrithione was employed in the form of Additive ZO3 (Microban Products Company, Huntersville NC). The Additive ZO3 was added at 7.2% to the acrylic binder, resulting in a concentration of antimicrobial agent in the relevant layer of about 5000 ppm. [0034] The food pad then was assessed for antimicrobial efficacy against Escherichia coli ("Eco"), Salmonella entriricus ("Sen"), Staphylococcus aureus ("Sau") and Listeria moncytogenes ("Lmo"). Antimicrobial efficacy evaluations were carried out using a modified AATCC Test Method 100 on food pads before and after 25 washings under cold running tap water. Results are shown in Table 1.

[0035] Controls, having no antimicrobial agent added, displayed no antimicrobial effect and did not inhibit microbial growth thereon. In all cases, substantial reductions in bacterial growth were observed in the experimental samples.

[0036] In addition, efficacy was observed even after 25 washings, demonstrating durability of the antimicrobial effect and persistent retention of the antimicrobial additive within the polymeric material of the food pad.

TABLE 1

EXAMPLE 2

[0037] A second exemplary food pad was manufactured using the same specifications as in Example 1 , except that the second exemplary sample utilized a silver-based antimicrobial compound marketed as Additive IB12 (Microban Products Company, Huntersville NC). The Additive IB12 was used at a concentration in the relevant layer of about 10,000 ppm (1 %). [0038] The food pad similarly was assessed for antimicrobial efficacy against Escherichia coli ("Eco"), Salmonella entriricus ("Sen"), Staphylococcus aureus ("Sau") and Listeria moncytogenes ("Lmo"). Antimicrobial efficacy evaluations were carried out using a modified AATCC

Test Method 100 on food pads, the results of which are presented in Table

2.

[0039] Controls lacking antimicrobial agent displayed no antimicrobial effect and did not inhibit microbial growth thereon. All experimental samples demonstrated substantial reductions in bacterial growth.

TABLE 2

Method 100, % reduction

Upper Layer Eco Sau Sen Lmo Control 0 0 0 0 Sample 99.9 77.2 99.9 91 .4

[0040] The food pad disclosed herein is suitable for use in ambient and/or refrigerated conditions. Ambient use can include, for example, placement on or in a countertop, table or other surface; cabinet; bowl; basket; or the like. Refrigerated environment usage preferably comprises placement in a crisper bin or vegetable/produce drawer, but can also include placing the pad on a shelf within a refrigerator, walk-in cooler, or other refrigerated compartment.

[0041] In use, fluids released from a foodstuff, e.g. fruit, placed on the present food pad 10 are deposited by gravity onto the food pad, where contact with the antimicrobial agent(s) incorporated therein can act to neutralize microbes in the fluid. In this manner, the contents of the fluid are kept more hygienic, as are foodstuffs in proximity to the food pad. [0042] The present food pad further effects a reduction in odor within the food storage area, as antimicrobial activity lessens rotting and the production of malodorous microbial waste.

[0043] It is to be understood that the foregoing description and specific embodiments are merely illustrative of the best mode of the invention and the principles thereof, and that various modifications and additions may be made to the apparatus by those skilled in the art, without departing from the spirit and scope of this invention.

Claims

CLAIMS What is claimed is:

1. An antimicrobial food pad, comprising: a first layer constructed of a synthetic polymeric material approved for food contact; and an antimicrobial agent substantially persistently disposed in the synthetic polymeric material, the antimicrobial agent approved for use in food contact; wherein the first layer exhibits antimicrobial activity four hours after challenge with either of Klebsiella pneumoniae or Staphylococcus aureus.

2. An antimicrobial food pad according to claim 1 , further comprising: a second layer constructed of a synthetic polymeric material; wherein at least one of the first layer and the second layer is a moisture-absorbent; and wherein the second layer optionally includes an antimicrobial agent disposed therein, the antimicrobial agent approved for use in food contact.

3. An antimicrobial food pad according to any of preceding claims, further comprising: a third layer constructed of a synthetic polymeric material; wherein the third layer optionally includes an antimicrobial agent disposed therein, the antimicrobial agent approved for use in food contact.

4. An antimicrobial food pad according to any of the preceding claims wherein the antimicrobial agent is at least one of 2,4,4'-trichloro-2'- hydroxydiphenyl ether; 2-phenylphenol; poly(hexamethylene biguanide) hydrochloride; 3,4,4'-trichlorocarbanilide; diiodomethyl p-tolylsulfone; azoles (such as propiconazoles, tebuconazoles); and isothiazolone-based compounds (such as 1 ,2-benzisothiazolin-3-one; N-butyl-1 ,2- benzisothiazolin-3-one; 2-octyl-isothiazolone; 4,5-dichloro-2-N-octyl-3(2H)- isothiazolone; methyl-3(2H)isothiazolone; or chloro-2-methyl-3(2H)- isothiazolone.

5. An antimicrobial food pad according to any of the preceding claims wherein the antimicrobial agent is at least one of titanium dioxide; barium monohydrate; barium metaborate(H₂0); a pyrithione compound such as zinc pyrithione, sodium pyrithione, and mixtures and derivatives thereof; a silver compound such as elemental, zeolitic, amorphous glass, sol-gel, and mixtures and derivatives thereof; a copper compound; or a zinc compound.

6. An antimicrobial food pad according to any of the preceding claims wherein the antimicrobial activity is retained after at least ten washings with water.

7. An antimicrobial food pad according to any of the preceding claims wherein the antimicrobial agent is present in the polymeric material at a concentration of at least about 500 ppm.

8. An antimicrobial food pad, comprising: an upper layer constructed of a top layer synthetic polymeric material approved for food contact; a bottom layer constructed of a bottom layer synthetic polymeric material; and an antimicrobial agent disposed in at least one of the top layer or bottom layer synthetic polymeric materials; wherein the layer in which the antimicrobial agent is disposed exhibits antimicrobial activity four hours after microbial challenge.

9. An antimicrobial food pad, comprising: an upper layer constructed of a first synthetic polymeric material approved for food contact; a bottom layer constructed of a second synthetic polymeric material; a intermediate layer constructed of a third synthetic polymeric material; and an antimicrobial agent disposed in at least one of the first, second, or third synthetic polymeric materials; wherein the layer in which the antimicrobial agent is disposed exhibits antimicrobial activity four hours after microbial challenge.

10. An antimicrobial food pad according to any of preceding claims 8 or 9 wherein the antimicrobial agent is present in the polymeric material in an efficacious amount and is substantially persistently disposed in the polymeric material.