GB2553756A

GB2553756A - Disinfection of foodstuffs

Info

Publication number: GB2553756A
Application number: GB1613333.2A
Authority: GB
Inventors: Robert Snowball Malcolm
Original assignee: Ultra Biotecs Ltd
Current assignee: Ultra Biotecs Ltd
Priority date: 2016-08-02
Filing date: 2016-08-02
Publication date: 2018-03-21
Anticipated expiration: 2036-08-02
Also published as: GB201613333D0; GB2553756B

Abstract

A foodstuff disinfecting apparatus 400 comprises a tank 401 holding liquid for receiving microorganisms from foodstuffs 19. The tank has a barrier 403 defining an open channel 404 through which liquid flows, and a region 407 holding stationary liquid adjacent at least one ultrasonic transducer 409 for emitting ultrasonic energy through the stationary liquid and through the barrier 403 into the liquid in channel 404. Foodstuff 19 is conveyed by a conveyor 18 into, along, and out of the liquid flowing through the channel 404 such that the ultrasonic energy forces microorganisms off the foodstuff and into the flowing liquid. A flow provider may produce a velocity of liquid flow through the channel based upon, e.g. matching, the speed of the conveyor. Contaminated liquid from the channel is preferably recirculated via a reservoir (450, fig. 4A) which disinfects the liquid by heating and/or filtering. The foodstuff may be meat, e.g. chicken or beef. In another embodiment the ultrasonic transducers (4, fig. 1) are directly attached to and emit through the walls of an inner tank (1, fig. 1) defining the channel, provided within an outer tank (2, fig. 1) defining the reservoir.

Description

(71) Applicant(s):

Ultra Biotecs Limited

Billing Road, NORTHAMPTON, NN1 5AN, United Kingdom (72) Inventor(s):

Malcolm Robert Snowball (56) Documents Cited:

WO 2009/115543 A1 CN 105750262 A US 6537600 B1 US 5939115 A US 20040251773 A1

CN 204811860 U FR 002918589A1 US 6138698 A US 20050061355 A1 (58) Field of Search:

INT CL A22B, A22C, A23N, A61L, B08B Other: WPI, EPODOC, TXTE.

(74) Agent and/or Address for Service:

Mathys & Squire LLP

The Shard, 32 London Bridge Street, LONDON, SE1 9SG, United Kingdom (54) Title of the Invention: Disinfection of foodstuffs Abstract Title: Disinfecting foodstuffs (57) A foodstuff disinfecting apparatus 400 comprises a tank 401 holding liquid for receiving microorganisms from foodstuffs 19. The tank has a barrier 403 defining an open channel 404 through which liquid flows, and a region 407 holding stationary liquid adjacent at least one ultrasonic transducer 409 for emitting ultrasonic energy through the stationary liquid and through the barrier 403 into the liquid in channel 404. Foodstuff 19 is conveyed by a conveyor 18 into, along, and out of the liquid flowing through the channel 404 such that the ultrasonic energy forces microorganisms off the foodstuff and into the flowing liquid. A flow provider may produce a velocity of liquid flow through the channel based upon, e.g. matching, the speed of the conveyor. Contaminated liquid from the channel is preferably recirculated via a reservoir (450, fig. 4A) which disinfects the liquid by heating and/or filtering. The foodstuff may be meat, e.g. chicken or beef. In another embodiment the ultrasonic transducers (4, fig. 1) are directly attached to and emit through the walls of an inner tank (1, fig. 1) defining the channel, provided within an outer tank (2, fig. 1) defining the reservoir.

405

407

1/6

Figure 1

2/6

Figure 2

3/6

Figure 3

Figure 4A

450

Figure 4B

5/6

Figure 5B

6/6

405 407

Figure 6

DISINFECTION OF FOODSTUFFS

Background of the invention

This invention relates to a method and apparatus for the sterilisation or disinfection of products such as foodstuffs and in particular but not solely to meat.

The shelf life of food is substantially shortened due to the presence of micro-organisms in the food, which can cause the food to deteriorate. Not only does shelf life affect the economic viability of food producers but it has a direct effect on public health, since the presence of certain micro-organisms in food can be hazardous if the food is ingested. These problems can be exacerbated if the food is not kept sufficiently refrigerated or is undercooked, since the micro-organisms in the food can multiply rapidly.

In order to overcome the above-mentioned problems, it has been proposed to pasteurise food. However, a disadvantage of pasteurisation is that the process is lengthy and can only be used on certain types of food. Furthermore, the pasteurisation process affects the taste of the food and is costly to perform, since it uses a substantial amount of energy, a great deal of which is discharged into the working environment.

In one known method, the food is packaged in an atmosphere which inhibits the fast reproduction of micro-organisms. One such an approach is to package the food product within a carbon dioxide atmosphere. This has proved to be difficult to control, environmentally unfriendly and expensive to run. It also does not kill pathogenic microorganisms but instead merely slows down their reproduction rate.

Independent tests have shown that the new invention is particularly good at disinfecting the surface of meat without imparting any taste, change of texture or change of colour.

The micro-organisms which infect meat are particularly difficult to disinfect without changing the organoleptic qualities of the meat, Campylobacter on chicken and Ecoli 0157 on beef being particularly difficult to eradicate.

Another feature of meat is that its surface is covered with micro-cracks, fissures and pores which provide protection for the micro-organisms and prevent easy access to disinfectants.

Thermal disinfection processes such as steam or water scalding, for example at 100°c seriously degrade the product and are not acceptable to either the food manufacturers or the retailers.

Strong chemicals and biocides are not acceptable because they impart objectionable tastes and or smells, and are banned for the processing of chicken in Europe.

UV disinfection although being efficient and fast in killing micro-organisms is unable to thoroughly disinfect meat as it can only kill micro-organisms that are exposed to the UV light; unfortunately a high proportion of the micro-organisms are not exposed but hidden from the UV light, usually by the poor transmissivity of the water as it fouls over time.

The solution to this problem is a process which removes the micro-organisms from the surface and pores of the meat without changing its organoleptic qualities into a medium such as water so that they can then be exposed to some form of disinfection and be deactivated or killed.

Previous work done with ultrasonic wave energy has shown that there is a disinfection effect on micro-organisms due to the implosion effect of collapsing vacuum bubbles caused by the Ultrasonic wave energy and the shear stresses caused by the implosion phenomenon. There is also evidence that this shearing effect causes the formation of free radicals stripped from the water.

Microbiologists have established that the proteins which make up the DNA of microorganisms start to congeal at 55°C - 65°C and if enough of these proteins congeal quickly then the microorganism dies quickly.

Suitable disinfectors are UV radiation, Ultrasonic wave energy and hot water between 55°C and 90°C. Preferably the disinfection system is Ultrasonic wave energy and hot water.

Work done with hot water as a disinfector shows that it is a fast efficient disinfector but to some products which are temperature sensitive it can cause unacceptable damage.

Testing carried out on whole chicken has shown that with short treatment times 75°C is acceptable, 80 °C is marginal and 85°C is unacceptable. For some microorganisms, short treatment times will not give the required kill rate and increasing the treatment time causes damage to the product, therefore with heat sensitive products this becomes a major problem.

The following invention addresses the aforementioned problem.

Summary of the invention

Aspects of the invention are as set out in the independent claims and optional features are set out in the dependent claims. Aspects of the invention may be provided in conjunction with each other and features of one aspect may be applied to other aspects.

Drawings

Embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a partial sectional view of an ultrasonic tank supported inside an outer tank;

Figure 2 shows a side view of an ultrasonic tank supported inside an outer tank;

Figure 3 shows a plan view of ultrasonic tank with submerged heaters, shallow wide tank;

Figure 4A shows a perspective view of an example disinfecting apparatus;

Figure 4B shows a side cross-section of the disinfecting apparatus of Figure 4A;

Figure 5A shows a plan view of the disinfecting apparatus of Figure 4A;

Figure 5B shows an end view of the disinfecting apparatus of Figure 4A; and

Figure 6 shows an end cross-section of a tank of the disinfecting apparatus of Figure 4A.

Specific description

Tests carried out by the inventor has shown that there is not a single process which satisfactorily disinfects the product rather it has been shown that two synergistic processes working together gives a good disinfection result (4-5 log micro-organism reduction). The preferred process comprises ultrasonic wave energy combined with hot water.

In a first embodiment and with reference to Figures 1 & 2 - A substantially rectangular inner tank 1 positioned inside a rectangular outer tank 2 and supported from brackets 3 rigidly attached to the inside wall of the outer tank 2. The inner tank 1 has ultrasonic transducers 4 placed inside the tank to produce ultrasonic wave energy inside the inner tank 1. Preferably the ultrasonic transducers 4 are placed on the walls of the inner tank

1. Preferably the outer tank is heat insulated to minimize heat loss.

When the tank 1 is filled with a fluid e.g. a liquid such as water, and the ultrasonic transducer 4 is driven by an ultrasonic oscillator (not shown) then ultrasonic waves are generated from the ultrasonic transducer 4 which vibrate the fluid at the ultrasonic frequency in the range 20 kHz to 100 kHz; preferably the ultrasonic transducer 4 is of the magnetostriction or quartz crystal or ceramic type capable of developing powers greater than 500 Watts. Preferably the power of the ultrasonic transducer is greater than 1000 Watts.

Attached to the base of the inner tank via a flange 5 is a pipe 6 positioned to convey water from the inner tank 1 through the wall of the outer tank 2 via a watertight flange 7 to the inlet of a pump 8 where it is rigidly attached with water tight fittings 11. One end of pipe 17 is rigidly attached with water tight fittings 11 to the outlet of pump 8 and the other end is rigidly attached with water tight fittings 12 to the base of the outer tank 2 thus a watertight conduit is formed from and through the base of tank 1 through the pump 8 and through the base of the outer tank 2. The pipe 6 is joined by a flange 10 for ease of construction.

When the tanks 1 and 2 are filled with water up to the optimum water level 14 the inner tank is fully submerged and the water is heated either by a heater 16 directly in the tank or indirectly by a heat exchanger 16 system (not fully shown).

The operation of the invention will now be explained with the aid of Figure 1.

When in operation the steady state conditions are as follows;

The water is at the optimum level 14 and has been heated to the desired temperature by the heater 16. The pump 8 is switched “on and the ultrasonic transducers 4 are energized.

A conveyor 18 is positioned such that it travels over the inlet end of the inner tank 1 carrying the product 19 to be disinfected through the tank 1 at a depth coinciding with the center of the ultrasonic transducers 4. The product is conveyed through the tank 1 and out at the exit end of the tank 1. With the ultrasonic transducer 4 energized by the ultrasonic power oscillator (not shown) the microbiological contamination on the product 19 is forced off the product due to the ultrasonic wave energy causing a microscopic scrubbing effect on the surface of the product 13. The micro-organisms are forced into the water from the surface as well as from any micro-cracks, fissures and pores on the product 13. The pump forces the water to flow through the tank 1 in a downward flow carrying the microbiological contamination with it. Any clumps of slime may be broken down to individual microorganisms by the ultrasonic wave energy.

The contaminated water is conveyed through the pump 8 and into the outer tank 2 whose water is also at the desired temperature. The contaminated water at this point is moving at a fast forward velocity and makes contact with the baffle plate 15 which slows it down encouraging the contaminated water to stratify, although of course in other examples other types of baffle may be used. If the volume of the inner tank 1 is small in relation to the outer tank 2 then the rate of water flow through the inner tank will be fast but through the outer tank 2 will be much slower.

The contaminated water proceeds through the outer tank 2 and the relatively long time in the hot water kills the microbiological contamination meanwhile the disinfected water at the top of the outer tank keeps the inner tank permanently full and the process cycles continuously. Preferably the outer tank 2 is rigidly fixed to a base frame (not shown) which in turn is rigidly fixed to the floor.

If the treatment meets the acceptable temperature and time requirements for the product in the inner tank and the temperature and time requirements to kill the biological contamination in the outer tank then this invention addresses the aforementioned problem associated with temperature sensitive products.

For products contaminated with micro-organisms which are more resistant to heat and would need a disinfecting water temperature which is higher than the product can stand without unacceptable deterioration, the water temperature in the inner tank 1 must be lower than the water temperature in the outer tank 2. This allows the micro-organisms to be dislodged in acceptable low temperature water then transferred to high temperature water for disinfection.

In a second embodiment and referring to Figure 3 -- A substantially rectangular inner tank 1 positioned inside a rectangular outer tank 2 and supported from brackets 3 rigidly attached to the inside wall of the outer tank 2. The inner tank 1 has ultrasonic transducers 4 placed inside the tank to produce ultrasonic wave energy inside the inner tank 1. Preferably the ultrasonic transducers 4 are placed on the walls of the inner tank

1. Preferably the outer tank is heat insulated to minimize heat loss.

When the inner tank 1 is filled with a fluid e.g. water and the ultrasonic transducer 4 is driven by an ultrasonic power oscillator (not shown) then ultrasonic waves are generated from the ultrasonic transducer 4 which vibrate the fluid at the ultrasonic frequency in the range 20 kHz to 100 kHz; preferably the ultrasonic transducer 4 is of the magnetostriction or quartz crystal or ceramic type capable of developing powers greater than 500 Watts. Preferably the power of the ultrasonic transducer is greater than 1000 Watts.

Attached to the base of the inner tank via a flange 5 is a pipe 6 positioned to convey water from the inner tank 1 through the wall of the outer tank 2 via a watertight flange 7 to the inlet of a pump 8 where it is rigidly attached with water tight fittings 11. One end of pipel 7 is rigidly attached with water tight fittings 11 to the outlet of pump 8 and the other end is rigidly attached with water tight fittings 12 to the base of the outer tank 2 thus a watertight conduit is formed from and through the base of tank 1 through the pump 8 and through the base of the outer tank 2. The pipe 6 is joined by a flange 10 for ease of construction. When the inner tank 1 and outer tank 2 are filled with water up to the optimum water level 14 the inner tank is fully submerged.

The outer tank 2 is partitioned by a thermally insulated partition 21 rigidly fixed to the inside walls of the outer tank 2 by brackets 22 effectively making the outer tank 2 into two tanks an upper tank 23 and a lower tank 24.The water in the lower tank 24 is heated either by a heater 16 directly in the tank or indirectly by a heat exchanger 16 system (not fully shown).

A flow through chiller 20 is positioned with its input port 25 rigidly fixed with watertight fittings to and through the wall of the lower tank 24 and its output port 26 rigidly fixed with watertight fittings to and through the wall of the upper tank 23 so that any water flowing through the lower tank 24 will automatically flow through the chiller 20 and into the upper tank 23 and be cooled from its original disinfection temperature to a temperature which the product can be processed without sustaining unacceptable damage.

When the inner tank 1 and outer tank 2 are filled with water up to the optimum water level 14 the inner tank is fully submerged and the water in the lower tank 2 is heated either by a heater 16 directly in the tank or indirectly by a heat exchanger 16 system (not fully shown) to produce the disinfection temperature. When the disinfection temperature is reached the chiller 20 and the pump 8 are switched on and the system starts to circulate providing the correct process temperature in the upper tank 23 and the correct disinfection temperature in the lower tank 24.

The operation of the invention will now be explained with the aid of Fig 3.

When in operation the steady state conditions are as follows;

The water is at the optimum level 14 and has been heated to the desired temperature in the upper tank 23 via the chiller 20 and the desired disinfection temperature in the lower tank 24 by the heater 16. The chiller 20 and the pump 8 are switched on and the ultrasonic transducers 4 are energized.

A conveyor 18 is positioned such that it travels over the inlet end of the inner tank 1 carrying the product 19 to be disinfected through the inner tank 1 at a depth coinciding with the center of the ultrasonic transducers 4. The product is conveyed through the tank 1 and out at the exit end of the tank 1. With the ultrasonic transducer 4 energized by the ultrasonic power oscillator (not shown) the microbiological contamination on the product 19 is forced off the product due to the ultrasonic wave energy causing a microscopic scrubbing effect on the surface of the product 13. The micro-organisms are forced into the water from the surface as well as from any micro-cracks, fissures and pores on the product 13. The pump 8 forces the water to flow through the tank 1 in a downward flow carrying the microbiological contamination with it.

The contaminated water is conveyed through the pump 8 and into the lower tank 24 whose water is at the desired disinfection temperature. The contaminated water at this point is moving at a fast forward velocity and makes contact with the baffle plate 15 which slows it down encouraging the contaminated water to stratify. If the volume of the inner tank 1 is small in relationship to the outer tank 2 then the rate of water flow through the inner tank will be fast but through the outer tank 2 will be much slower.

The contaminated water proceeds through the lower tank 24 and the relatively long time in the hot water kills the microbiological contamination meanwhile the disinfected water at the top of the lower tank 24 flows into the inlet 25 of the chiller 20, through the chiller 20 to be cooled to the required processing temperature for the inner tank 1. Then the cooled and disinfected water flows out of the outlet 26 of the chiller 20 into the upper tank 23 and hence into the inner tank 1. The water level 14 keeps the inner tank permanently full and the process cycles continuously. Preferably the outer tank 2 is rigidly fixed to a base frame (not shown) which in turn is rigidly fixed to the floor.

This invention allows heat sensitive products to be processed by splitting the process into two distinct synergistic techniques. A technique for removing micro-organism contamination from a product 19, using ultrasonic wave energy, and into water at a temperature which does not cause unacceptable damage to the product 19 and quickly move the contaminated water into water at a high temperature to kill the micro-organism contamination, then deliver the disinfected water back into the inner tank 1 at the correct processing temperature.

There are several other example configurations that can be employed to achieve this solution;

1) The outer tank could be split into two distinct tanks with the chiller straddled between the two tanks.

2) The chiller 20 could be remote or the outer tank 2 could be split into three separate tanks with the chiller being the middle tank.

3) The heater 16 or heat exchanger 16 could be remote.

4) The inner tank can be positioned outside of the outer tank, for example separate to the outer tank, and the fluid pumped to it (for example horizontally), instead of being submerged in the outer tank.

These are but a few possible configurations and those skilled in the art will find different Configurations, nevertheless this should not detract from the scope of the invention as defined by the appended claims.

Preferably a water filter process is added to the tanks to remove oil, fat and general debris from the water to keep it clear. Several products are commercially available for this purpose and those skilled in the art of water treatment will be able to provide suitable schemes.

The whole process may be automatically controlled by a PLC to provide consistently high disinfection results.

In some examples the lower or outer tank 24 described above may be a reservoir. The volume of the outer tank or reservoir may be greater than that of the upper or inner tank

23. Accordingly, an aspect of the disclosure provides an apparatus for disinfecting a product, the apparatus comprising a tank arranged to provide ultrasonic energy to the product via a liquid such as water for forcing microorganisms off the product and into the liquid, and a reservoir arranged to receive and heat liquid transferred from the tank into the reservoir. The temperature of the liquid in the reservoir is selected to disinfect the microorganisms forced off the products into the liquid.

The apparatus may be configured to heat the liquid to the same temperature as the tank, or to a temperature hotter than that of the tank. For example, the apparatus may be configured to heat the liquid in the reservoir to a selected temperature, for example to at least 75°C. The reservoir may comprise at least one of a heater and a heat exchanger for heating the liquid to the selected temperature. The tank and/or reservoir may be insulated to inhibit heat loss from the liquid. In some examples, the reservoir may comprise a plurality of tanks.

The volume of the reservoir may be larger than that of the tank so that the liquid remains in the reservoir for longer than in the tank, for example so that the liquid remains in the tank for less than 5 s, and in the reservoir for at least 30 s.

The dwell time and temperature of the liquid in the reservoir may be selected to disinfect the microorganisms forced off the products into the liquid, for example so that the liquid remains in the reservoir at a temperature of at least 75°C for at least 30 s. The reservoir may comprise at least one baffle arranged to slow the flow of liquid through the reservoir (and hence increase the dwell time) for encouraging the liquid to stratify.

In some examples, the tank is inside the reservoir. In other examples the tank may be outside the reservoir. For example, the apparatus may be arranged to transfer liquid horizontally from the tank to the reservoir. The apparatus and/or reservoir may be configured to recirculate the liquid to the tank. The apparatus may further comprise a flow through chiller for cooling the recirculated liquid and/or a filter for filtering the recirculated liquid.

As shown in the Figures, in some examples the apparatus comprises a conveyor 18 for carrying the product 19 through the tank. The apparatus may also comprise an ultrasonic power oscillator coupled to the at least one ultrasonic transducer for driving the at least one ultrasonic transducer. The conveyor may carry the product through the liquid at a depth coinciding with the centre of the at least one ultrasonic transducer.

Another aspect of the disclosure is an apparatus for disinfecting products, for example foodstuffs such as meat, fruit and vegetables and nuts, for example as shown in Figures 4A to 6. The apparatus 400 comprises a tank 401 for holding a liquid for receiving microorganisms from the products 19. The tank 401 comprises a barrier 403 separating two regions of liquid. The first region 405 is arranged to provide an open channel 404 for the liquid through the tank 401 to enable a product 19 to be carried into, along, and out of a flowpath through the channel 404. The second region 407 holds liquid adjacent to at least one ultrasonic transducer for providing ultrasonic energy to the product via the liquid in the second region 407 and through the barrier 403 for forcing microorganisms off the product 900 and into the liquid in the first region 405.

An example apparatus is shown in Figures 4A to 6. The apparatus 400 comprises an elongate tank 401. As shown in Figure 6, the elongate tank 401 is substantially rectangular in cross-section and comprises two barriers 403 extending substantially the whole length of the tank 401 and separating two regions 405, 407 of liquid in the tank 401, although in other examples only one barrier 403 may be used. The barriers 403 define two sides of a channel 404 providing a flowpath for product 19 through the tank 401. The channel 404 corresponds to the first region 405, with the second region 407 being either side (or in some examples only to one side of) the channel 404.

In the example shown in Figure 6 the channel 404 is in the middle of the tank 401 and is deeper than the region 407 to either side of the channel 404, although in other examples the channel 404 may have the same depth as the rest of the tank 401. For example, the channel 404 may be 377 mm deep whereas the rest of the tank may be 317 mm deep. The length of the channel 404 may be 2865 mm. The width of the channel 404 may be 220 mm, whereas the width of the tank may be 654 mm.

The channel 404 is open, although the tank 401 may comprise a lid 415 covering a portion, for example a central portion, of the channel 404. The lid 415 is arranged to have openings for a conveyor 18 to carry product 19 into, through and out of the channel

404.

The barrier 403 is coupled to a wall of the tank 401 along its bottom edge. The coupling and the barrier 403 are watertight, for example the barrier 403 may be made from an impermeable material such as glass or metal (such as stainless steel), so that the two regions 405, 407 of liquid are kept separate. In some examples, the liquid held in the second region 407 is different to the liquid held in the first region 405. For example, the liquid held in second region 407 may be deionised water while the liquid held in the first region 405 may be normal tap water.

In some examples the barrier 403 comprises a material having an acoustic impedance greater than that of water. For example, the barrier may comprise a material having an acoustic impedance of at least 12 x 10⁶ kg/m²sec, for example at least 35 x 10⁶kg/m²sec. The barrier may be 3-6 mm thick, for example the barrier may be 18 to 22 gauge stainless steel.

The tank 401 comprises a plurality of ultrasonic transducers 409 arranged along the channel 404, although it will be understood that in some examples only one ultrasonic transducer 409 is used. The plurality of ultrasonic transducers 409 may be arranged either side of the channel 404, for example mirroring each other, or along only one side of the channel 404. The plurality of ultrasonic transducers 409 are evenly spaced along the length of the channel 404. The plurality of ultrasonic transducers 409 may extend substantially the whole height of the tank 401 and/or channel 404. The plurality of ultrasonic transducers 409 may be phase linked and/or synchronised, for example synchronised in frequency.

Each ultrasonic transducer 409 is coupled to a wall of the tank 401 inside the tank 401. In this way, each ultrasonic transducer 409 defines a boundary of the liquid in the second region 407. For example, each ultrasonic transducer 409 may form a wall of the tank 401.

The barrier 403 may comprise a respective window for each ultrasonic transducer 409 for transmitting ultrasonic pressure waves from the second region 407 to the first region

405. The size of each window may be selected based on the size of the corresponding ultrasonic transducer 409. Each respective window may be acoustically insulated from the other windows, for example by a strip of insulating material such as rubber. The distance between a window in the barrier 403 and the corresponding ultrasonic transducer 409 may be greater than the wavelength of ultrasonic pressure waves produced by the ultrasonic transducer. For example, the distance between the at least one window and the ultrasonic transducer 409 may be greater than 35 mm, for example greater than 50 mm, preferably 63 mm.

The apparatus 400 also comprises a second tank or reservoir 450 arranged to receive and heat liquid transferred from the (first) tank 401 comprising the barrier 403 separating the two regions 405, 407. In the example shown in Figures 4A to 6, the second tank or reservoir 450 comprises two separate vessels in fluid communication, although in other examples the second tank or reservoir 450 may only comprise one vessel.

The second tank or reservoir 450 is coupled to the (first) tank 401 by a pipe 451. In the example shown in Figures 4A to 6, the tank 401 and reservoir 450 are at the same height (for example they are mounted on the same surface), although it will be understood that in other examples the tank 401 and reservoir 450 may be a different heights, or for example the tank 401 may be inside the reservoir 450, similar to the examples shown in Figures 1 to 3 and described above.

As with the examples shown in Figures 1 to 3, the reservoir 450 comprises a heater 16. The heater 16, for example, may comprise submerged heating elements in the reservoir 450. The heater 16 may also comprise a temperature sensor. The reservoir 450 also comprises a baffle or series of baffles such as the baffles 15 described above. The volume of the second tank or reservoir 450 is greater than that of the (first) tank 401. For example, the volume of the (first) tank 401 may be 339 litres and the volume of the reservoir 1447 litres, although if the reservoir comprise two vessels, the total volume (i.e. capacity) of the reservoir may be double this. In some examples, the reservoir 450 may also comprise a filter and additionally or alternatively a chiller for cooling the liquid.

Coupled to the tank 401 is a flow provider 420. The flow provider 420 may comprise a pump, such as an impeller pump. In the example shown, the flow provider 420 is in-line with the pipe 451 coupling the reservoir to the tank 401. As noted above, the apparatus 400 also comprises a conveyor 18 for carrying the product 19 through the liquid in the channel 404. The conveyor 18 may have baskets or hooks for carrying and dipping the product 19 in the liquid in the channel 404.

The ultrasonic transducers 409 are operable to provide ultrasonic energy to the product 19 through the liquid in the second region 407, through the barrier 403, and through the liquid in the first region 405. The channel 404 and lid 415 are arranged so that the conveyor 18 carrying the product 19 can carry the product into, through and out of the liquid in the channel 404, as shown in Figures 4A and 4B. The position of the ultrasonic transducers 409 may be selected to provide ultrasonic energy to the centre of the product 19 when the product is submerged in the liquid of the channel 404.

If the barrier 403 comprises a window, the window is configured to transmit ultrasonic energy from liquid on one side of the barrier 403 to liquid on the other side of the barrier 403. The degree of ultrasonic energy provided to the product by the ultrasonic transducers 409 is selected to dislodge or force microorganisms from the surface of the product 19 into the liquid.

The flow of product 19 through the channel 404 creates a flowpath that draws liquid along with the product 19 in the channel 404. This flow of product 19 can create turbulence in the liquid. The flow provider 420 coupled to the tank 401 is arranged to provide a flow of liquid through the channel 404 in the first region 405 at a velocity selected based on that of the conveyor 18 carrying the product through the liquid. For example, the flow provider 420 may be configured to adjust the flow rate of liquid through the channel 404 to match the velocity of the product 19 being carried by the conveyor 18. Matching the velocity of the liquid through the channel 404 to that of the product 19 may help to reduce turbulence (and thereby the creation of undesirable bubbles in the liquid) and hence increase the efficacy of the transmission of ultrasonic energy to the product 19 from the ultrasonic transducers 409. In some examples, the flow provider 420 may have an output with a cross-sectional area that is selected or adjusted to provide a substantially laminar flow through the channel at the velocity selected based on that of the conveyor 18. The flow provider 420 may also be operable to control the flow of liquid from the tank 401 to the reservoir 450 and thereby recirculate liquid through the apparatus 400.

The tank 401 may hold the liquid in the second region 407 (adjacent to the ultrasonic transducers 409) at a relatively stationary velocity. Because the liquid adjacent to the ultrasonic transducers 409 is relatively stationary, this again may increase the efficacy of the transmission of ultrasonic energy to the product 19.

Operation of the ultrasonic transducers 409, the flow provider 420 and the conveyor 18 may be controlled by a programmable logic circuit, PLC. The PLC may also be configured to control the temperature of the liquid (for example by controlling operation of a heater 16 or a chiller 20 as described above). In some examples, the PLC may be configured to receive signals, for example from a temperature sensor for detecting the temperature of the liquid in the reservoir 450, or a flow meter for detecting the velocity of the liquid in the tank 401, and adjusting the outputs for the heater 16 or flow provider 420 as appropriate.

The baffles 15 in the reservoir 450 are arranged to slow the flow of liquid through the reservoir 450, thereby encouraging the liquid and any debris carried by the liquid to stratify. For example, the baffles 15 may be arranged to provide a labyrinth-like flow path through the reservoir 450 and/or extend the flow path for liquid through the reservoir 450, for example the baffles 15 may provide a serpentine flow path through the reservoir 450. The baffles 15 may be configured to cause the flow path to perform a series of U-turns or 180° turns. The heater 16 is operable to heat the liquid in the reservoir to a selected temperature, for example a selected disinfection temperature such as 75°, for example 80°C, for example 85°C, and/or may use an optional temperature sensor as a feedback mechanism to operate at the selected temperature.

The reservoir 450 is configured to treat (for example disinfect) the liquid being circulated through the apparatus 400. The flow provider 420, the volume of the reservoir 450 and the selection and arrangement of baffles 15 may be configured to adjust the dwell time of fluid in the reservoir and thereby the treatment time of the fluid in the reservoir 450.

In use, the product 19 is carried by the conveyor 18 into, through and out of the channel 404 of the tank 401. The speed of the conveyor 18 and/or the length of the channel 404 (and hence the dwell time of the product in the liquid of the channel 404) may be adjusted based on the ultrasonic energy applied to the product and/or the temperature of the liquid in the channel 404, but may be at least 5 seconds, for example at least 6.5 seconds. The conveyor 18 may carry the product at a speed of, for example, 0.5 m per second, resulting in 12,000 products being processed per hour.

The ultrasonic transducers 409 provide energy to the product via the second 407 and first 405 regions (and through the barrier 403) which act to dislodge and scrub the product 19 to force microorganisms off the product 19 and into the liquid in the channel 404. The liquid in the channel 404 is driven along by the flow provider 420 so that liquid is recirculated from the tank 401, through the pipe 451 to the reservoir 450. As the liquid enters the reservoir 450, it is slowed by the baffles 15 and the volume of liquid in the reservoir 450. As the liquid slows it begins to stratify. The heater 16 acts to heat the liquid to the selected temperature (for example a selected disinfection temperature such as 75°C. The arrangement of the baffles 15, the volume of the reservoir 450 and the flow rate provided by the flow provider 420 is selected to control the dwell time of liquid in the reservoir. The dwell time and the temperature of the liquid in the reservoir are selected to disinfect the liquid and to kill any microorganisms forced off the product 19 into the liquid, for example as described in other aspects of the disclosure. For example the dwell time may be selected to be at least 30 seconds.

Once the liquid passes through the reservoir 450, before it passes to the flow provider 420 it may be filtered by an optional filter, and/or it may be cooled by a chiller (such as chiller 20 described above) so that the temperature of the liquid does not damage or degrade the product 19.

In examples where the reservoir 450 comprises two vessels, each vessel may be configured to have a different temperature and/or dwell time. For example, each vessel may act so as to serve a different purpose. For example, one vessel may have a high temperature to kill microorganisms, and the other vessel may act to cool the liquid to a temperature acceptable for recirculating to the product 19. Additionally or alternatively, each vessel may have a different size and/or volume.

In some examples the temperature of the liquid in the tank 401 is the same as the temperature of the liquid in the reservoir 450, although in other examples the temperature of the liquid in the reservoir 450 is hotter than the liquid in the tank 401.

In some examples, the tank 400 may also comprise a run-off weir along the top edge of the channel 404. The run-off weir may be configured to collect debris/oils/fats forced off the product 19 by the ultrasonic energy. Apparatuses described herein may be configured to disinfect foodstuffs, for example meat such as chicken or beef, fruit and vegetables and nuts.

With reference to the drawings in general, it will be appreciated that schematic functional block diagrams are used to indicate functionality of systems and apparatus described herein. It will be appreciated however that the functionality need not be divided in this way, and should not be taken to imply any particular structure of hardware other than that described and claimed below. The function of one or more of the elements shown in the drawings may be further subdivided, and/or distributed throughout apparatus of the disclosure. For example, the function of the flow provider 420 may be distributed throughout the apparatus 400. In some embodiments the function of one or more elements shown in the drawings may be integrated into a single functional unit.

The above embodiments are to be understood as illustrative examples. Further embodiments are envisaged. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. For example, any of the features of the exampled described in relation to Figures 1 to 3, may be used with the example of Figures 4A to 6. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

In some examples, one or more memory elements can store data and/or program instructions used to implement the operations described herein. Embodiments of the disclosure provide tangible, non-transitory storage media comprising program instructions operable to program a processor to perform any one or more of the methods described and/or claimed herein and/or to provide data processing apparatus as described and/or claimed herein.

The activities and apparatus outlined herein may be implemented with fixed logic such as assemblies of logic gates or programmable logic such as software and/or computer program instructions executed by a processor. Other kinds of programmable logic include programmable processors, programmable digital logic (e.g., a field programmable gate array (FPGA), an erasable programmable read only memory (EPROM), an electrically erasable programmable read only memory (EEPROM)), an application specific integrated circuit, ASIC, or any other kind of digital logic, software, code, electronic instructions, flash memory, optical disks, CD-ROMs, DVD ROMs, magnetic or optical cards, other types of machine-readable mediums suitable for storing electronic instructions, or any suitable combination thereof.

Claims

CLAIMS:

1. An apparatus for disinfecting products, the apparatus comprising:

a tank for holding a liquid for receiving microorganisms from the products; wherein the tank comprises a barrier separating two regions of liquid, wherein:

the first region is arranged to provide an open channel for the liquid through the tank to enable a product to be carried into, along, and out of a flowpath through the channel; and the second region holds liquid adjacent to at least one ultrasonic transducer for providing ultrasonic energy to the product via the liquid in the second region and through the barrier for forcing microorganisms off the product and into the liquid in the first region.

2. The apparatus of claim 1 wherein:

the apparatus comprises a conveyor for carrying the product through the liquid; and wherein the apparatus comprises a flow provider arranged to provide a flow of liquid through the channel in the first region at a velocity selected based on that of the conveyor carrying the product through the liquid; and the tank holds the liquid in the second region at a relatively stationary velocity.

3. The apparatus of claim 2 wherein the flow provider is configured to adjust the flow rate of liquid through the channel to match the velocity of the product being carried by the conveyor.

4. The apparatus of claim 2 or 3 wherein the flow provider has an output with a cross-sectional area sufficient to provide a substantially laminar flow through the channel at the velocity selected based on that of the conveyor.

5. The apparatus of any of the previous claims wherein the barrier comprises a window with a size selected based on the size of the at least one ultrasonic transducer, for transmitting ultrasonic pressure waves from the second region to the first region.

6.

The apparatus of any of the previous claims wherein the barrier comprises a material having an acoustic impedance greater than that of water.

7. The apparatus of any of the previous claims wherein the barrier comprises a material having an acoustic impedance of at least 12 x 106 kg/m2sec, for example at least 35 x 106 kg/m2sec.

8. The apparatus of any of the previous claims wherein the liquid held in the second region is different to the liquid held in the first region.

9. The apparatus of any of the previous claims wherein the ultrasonic transducer is coupled to a wall of the tank inside the tank.

10. The apparatus of any of the previous claims comprising a plurality of ultrasonic transducers arranged along the flowpath.

11. The apparatus of claim 10 wherein the plurality of ultrasonic transducers are phase linked and/or synchronised, for example synchronised in frequency.

12. The apparatus of claim 10 or 11, as dependent on claim 5, or any claim dependent thereon, wherein the barrier comprises a respective window for each ultrasonic transducer.

13. The apparatus of claim 12 wherein each respective window is acoustically insulated from the other windows.

14. The apparatus of claim 5, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than the wavelength of ultrasonic pressure waves produced by the ultrasonic transducer.

15. The apparatus of claim 5, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than 35 mm, for example greater than 50mm, preferably 63 mm.

16. The apparatus of any of the previous claims comprising a reservoir arranged to receive and heat liquid transferred from the tank comprising the barrier separating the two regions, wherein the temperature of the liquid in the reservoir is selected to disinfect the microorganisms forced off the products into the liquid.

17. An apparatus for disinfecting a product, the apparatus comprising:

a tank arranged to provide ultrasonic energy to the product via a liquid for forcing microorganisms off the product and into the liquid;

a reservoir arranged to receive and heat liquid transferred from the tank into the reservoir;

wherein the temperature of the liquid in the reservoir is selected to disinfect the microorganisms forced off the products into the liquid.

18. The apparatus of claim 16 or 17 wherein the reservoir is configured to heat the liquid to a higher temperature than the tank, for example to at least 75°C.

19. The apparatus of any of claims 16 to 18 wherein the volume of the reservoir is configured to be larger than that of the tank so that the liquid remains in the reservoir for longer than in the tank, for example so that the liquid remains in the tank for less than 5 s, and in the reservoir for at least 30 s.

20. The apparatus of claim 19 wherein the dwell time and temperature of the liquid in the reservoir is selected to disinfect the microorganisms forced off the products into the liquid, for example so that the liquid remains in the reservoir at a temperature of at least 75°C for at least 30 s.

21. The apparatus of any of claims 16 to 20 wherein the reservoir comprises at least one baffle arranged to slow the flow of liquid through the reservoir for encouraging the liquid to stratify.

22. The apparatus of any of claims 16 to 21 wherein the tank is inside the reservoir.

23. The apparatus of any of claims 16 to 22 wherein the apparatus is arranged to transfer liquid horizontally from the tank to the reservoir.

24. The apparatus of any of claims 16 to 23 further comprising a conveyor for carrying the product through the tank.

25. The apparatus of any of claims 16 to 24 wherein the reservoir comprises at least one of a heater and a heat exchanger for heating the liquid to the selected temperature.

26. The apparatus of any of claims 16 to 25 wherein the reservoir is configured to recirculate the liquid to the tank.

27. The apparatus of claim 26 further comprising a flow through chiller for cooling the recirculated liquid.

28. The apparatus of any of claims 16 to 27 wherein the temperature of the liquid in the reservoir is at least 75°C.

29. The apparatus of any of claims 16 to 28 wherein the reservoir is insulated to inhibit heat loss from the liquid.

30. The apparatus of claim 27 or any claim dependent thereon wherein the apparatus further comprises a filter for filtering the recirculated liquid.

31. The apparatus of any of the previous claims further comprising an ultrasonic power oscillator coupled to the at least one ultrasonic transducer for driving the at least one ultrasonic transducer.

32. The apparatus of claim 24, or any claim dependent thereon, wherein the conveyor carries the product through the liquid at a depth coinciding with the centre of the at least one ultrasonic transducer.

33. The apparatus of any of the previous claims wherein the liquid is water.

34. The apparatus of any of the previous claims further comprising a programmable logic circuit, PLC, configured to control at least one of: the delivery of ultrasonic energy to the liquid, the flow rate of the liquid and the temperature of the liquid.

35. The apparatus of any of the previous claims wherein the apparatus is configured to disinfect foodstuffs.

[for example meat such as chicken or beef, fruit and vegetables and nuts]

36. An apparatus substantially as described herein with reference to the accompanying drawings.

37. A method for disinfecting products, the method comprising:

holding a liquid for receiving microorganisms from the products in a tank in two regions separated by a barrier;

carrying products into, along, and out of a flowpath through an open channel of liquid in the first region; and delivering ultrasonic energy via the liquid in the second region and through the barrier to the products in the first region, for forcing microorganisms off the products and into the liquid in the first region.

38. The method of claim 37 comprising adjusting the flow rate of liquid through the channel to match the velocity of the product being carried by the conveyor.

39. The method of claim 37 or 38 comprising adjusting the flow rate of liquid throught the channel to provide a substantially laminar flow through the channel.

40. The method of any of claims 37 to 39 comprising flowing the liquid through the channel in the first region at a velocity based on that of the product being carried through the liquid; and holding the liquid in the second region at a relatively stationary velocity.

41. The method of any of claims 37 to 40 wherein comprising transmitting ultrasonic pressure waves from the second region to the first region through a window in the barrier.

42. The method of any of claims 37 to 41 wherein the barrier comprises a material having an acoustic impedance greater than that of water.

43. The method of any of claims 37 to 42 wherein the barrier comprises a material having an acoustic impedance of at least 12 x 106 kg/m2sec, for example at least 35 x 106 kg/m2sec.

44. The method of any of claims 37 to 43 wherein the liquid held in the second region is different to the liquid held in the first region.

45. The method of any of claims 37 to 44 wherein the ultrasonic energy is delivered to the products by at least one ultrasonic transducer coupled to a wall of the tank inside the tank.

46. The method of claim 45 comprising a plurality of ultrasonic transducers arranged along the flowpath.

47. The method of claim 46 wherein the plurality of ultrasonic transducers are phase linked and/or synchronised.

48. The method of claim 46 or 47, as dependent on claim 41, or any claim dependent thereon, wherein the barrier comprises a respective window for each ultrasonic transducer.

49. The method of claim 48 wherein each respective window is acoustically insulated from the other windows.

50. The method of claim 41, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than the wavelength of ultrasonic pressure waves produced by the ultrasonic transducer.

51. The method of claim 41, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than 50mm, preferably 63 mm.

52. The method of any of claims 37 to 51 further comprising transferring liquid from the tank comprising the barrier separating the two regions to a reservoir, and heating the liquid in the reservoir to a temperature selected to disinfect the microorganisms forced off the products into the liquid.

53. A method for disinfecting a product, the method comprising:

provide ultrasonic energy to the product via a liquid in a tank for forcing microorganisms off the product and into the liquid;

transferring liquid from the tank into a reservoir;

heating the liquid in the reservoir to a temperature selected to disinfect the microorganisms forced off the products into the liquid.

54. The method of claim 52 or 53 comprising heating the liquid in the reservoir to a higher temperature than the tank.

55. The method of claim 52, 53 or 54 comprising retaining the liquid in the reservoir for longer than in the tank, for example retaining the liquid in the reservoir for less than 5 s, and in the reservoir for at least 30 s.

56. The method of claim 55 wherein the dwell time and temperature of the liquid in the reservoir are selected to disinfect the microorganisms forced off the products into the liquid, for example so that the liquid remains in the reservoir at a temperature of at least 75°C for at least 30 s.

57. The method of any of claims 52 to 56 comprising slowing the flow of liquid through the reservoir via a baffle arranged to encourage the liquid to stratify.

58. The method of any of claims 52 to 57 wherein the tank is inside the reservoir.

59. The method of any of claims 52 to 58 further comprising carrying the product through the tank via a conveyor.

60. The method of any of claims 52 to 59 comprising heating the liquid to the selected temperature with at least one of a heater and a heat exchanger.

61. The method of any of claims 52 to 60 comprising recirculating the liquid.

62. The method of claim 61 further comprising cooling the recirculated liquid.

63. The method of any of claims 52 to 62 comprising heating the liquid in the reservoir to at least 75°C.

64. The method of any of claims 52 to 63 wherein the reservoir is insulated to inhibit heat loss from the liquid.

65. The method of any of claims 34 to 64 further comprising controlling at least one of: the delivery of ultrasonic energy to the liquid, the flow rate of the liquid and the temperature of the liquid with a programmable logic circuit, PLC.

35

66. The method of any of claims 34 to 65 wherein the method is a method for disinfecting foodstuffs.

27 07 17

Intellectual

Property

Office

Application No: GB1613333.2 Examiner: Mr Brendan Donohoe

65. The method of claim 61 or any claim dependent thereon comprising filtering the 5 recirculated liquid.

66. The method of any of claims 37 to 65 further comprising driving the at least one ultrasonic transducer with an ultrasonic power oscillator coupled to the at least one ultrasonic transducer.

io

67. The method of claim 59, or any claim dependent thereon, comprising carrying the product through the liquid at a depth coinciding with the centre of the at least one ultrasonic transducer.

15

68. The method of any of claims 37 to 67 wherein the liquid is water.

69. The method of any of claims 37 to 68 further comprising controlling at least one of: the delivery of ultrasonic energy to the liquid, the flow rate of the liquid and the temperature of the liquid with a programmable logic circuit, PLC.

70. The method of any of claims 37 to 69 wherein the method is a method for disinfecting foodstuffs.

71. A method substantially as described herein with reference to the accompanying 25 drawings.

27 07 17

AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS

CLAIMS:

1. An apparatus for disinfecting products, the apparatus comprising:

a tank for holding a liquid for receiving microorganisms from the products;

5 wherein the tank comprises a barrier separating the tank to provide two regions of liquid, wherein:

the first region is arranged to provide an open channel for the liquid through the tank to enable a product to be carried into, along, and out of a flowpath through the channel; and io the second region holds liquid adjacent to at least one ultrasonic transducer for providing ultrasonic energy to the product via the liquid in the second region and through the barrier for forcing microorganisms off the product and into the liquid in the first region; and wherein the apparatus comprises:

15 a conveyor for carrying the product through the liquid; and a flow provider arranged to provide a flow of liquid through the channel in the first region at a velocity selected based on that of the conveyor carrying the product through the liquid.

20 2. The apparatus of claim 1 wherein the tank holds the liquid in the second region at a relatively stationary velocity.

3. The apparatus of claim 1 or 2 wherein the flow provider is configured to adjust the flow rate of liquid through the channel to match the velocity of the product being carried

25 by the conveyor.

4. The apparatus of claim 1, 2 or 3 wherein the flow provider has an output with a cross-sectional area sufficient to provide a substantially laminar flow through the channel at the velocity selected based on that of the conveyor.

35 6.

The apparatus of any of the previous claims wherein the barrier comprises a

27 07 17 material having an acoustic impedance greater than that of water.

7. The apparatus of any of the previous claims wherein the barrier comprises a material having an acoustic impedance of at least 12 x 106 kg/m2sec, for example at

5 least 35 x 106 kg/m2sec.

io 9. The apparatus of any of the previous claims wherein the ultrasonic transducer is coupled to a wall of the tank inside the tank.

12. The apparatus of claim 10 or 11, as dependent on claim 5, or any claim

20 dependent thereon, wherein the barrier comprises a respective window for each ultrasonic transducer.

30 15. The apparatus of claim 5, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than 35 mm, for example greater than 50mm, preferably 63 mm.

16. The apparatus of any of the previous claims comprising a reservoir arranged to

35 receive and heat liquid transferred from the tank comprising the barrier separating the

27 07 17 two regions, wherein the temperature of the liquid in the reservoir is selected to disinfect the microorganisms forced off the products into the liquid.

17. The apparatus of claim 16 wherein the reservoir is configured to heat the liquid to 5 a higher temperature than the tank, for example to at least 75°C.

18. The apparatus of any of claims 16 or 17 wherein the volume of the reservoir is larger than that of the tank so that the liquid remains in the reservoir for longer than in the tank, for example so that the liquid remains in the tank for less than 5 s, and in the io reservoir for at least 30 s.

19. The apparatus of claim 18 wherein the dwell time and temperature of the liquid in the reservoir is selected to disinfect the microorganisms forced off the products into the liquid, for example so that the liquid remains in the reservoir at a temperature of at least

15 75°C for at least 30 s.

20. The apparatus of any of claims 16 to 19 wherein the reservoir comprises at least one baffle arranged to slow the flow of liquid through the reservoir for encouraging the liquid to stratify.

21. The apparatus of any of claims 16 to 20 wherein the tank is inside the reservoir.

22. The apparatus of any of claims 16 to 21 wherein the apparatus is arranged to transfer liquid horizontally from the tank to the reservoir.

23. The apparatus of any of claims 16 to 22 wherein the reservoir comprises at least one of a heater and a heat exchanger for heating the liquid to the selected temperature.

24. The apparatus of any of claims 16 to 23 wherein the reservoir is configured to 30 recirculate the liquid to the tank.

25. The apparatus of claim 24 further comprising a flow through chiller for cooling the recirculated liquid.

35 26. The apparatus of any of claims 16 to 25 wherein the temperature of the liquid in

27 07 17 the reservoir is at least 75°C.

27. The apparatus of any of claims 16 to 26 wherein the reservoir is insulated to inhibit heat loss from the liquid.

28. The apparatus of claim 25 or any claim dependent thereon wherein the apparatus further comprises a filter for filtering the recirculated liquid.

29. The apparatus of any of the previous claims further comprising an ultrasonic io power oscillator coupled to the at least one ultrasonic transducer for driving the at least one ultrasonic transducer.

30. The apparatus of any of the previous claims wherein the conveyor carries the product through the liquid at a depth coinciding with the centre of the at least one

15 ultrasonic transducer.

31. The apparatus of any of the previous claims wherein the liquid is water.

32. The apparatus of any of the previous claims further comprising a programmable 20 logic circuit, PLC, configured to control at least one of: the delivery of ultrasonic energy to the liquid, the flow rate of the liquid and the temperature of the liquid.

33. The apparatus of any of the previous claims wherein the apparatus is configured to disinfect foodstuffs.

34. A method for disinfecting products, the method comprising:

carrying products into, along, and out of a flowpath through an open channel of 30 liquid in the first region;

delivering ultrasonic energy via the liquid in the second region and through the barrier to the products in the first region, for forcing microorganisms off the products and into the liquid in the first region; and flowing the liquid through the channel in the first region at a velocity based on that 35 of the product being carried through the liquid;.

27 07 17

35. The method of claim 34 comprising adjusting the flow rate of liquid through the channel to match the velocity of the product being carried by the conveyor.

5 36. The method of claim 34 or 35 comprising adjusting the flow rate of liquid through the channel to provide a substantially laminar flow through the channel.

37. The method of any of claims 34 to 36 comprising holding the liquid in the second region at a relatively stationary velocity.

io

38. The method of any of claims 34 to 37 wherein comprising transmitting ultrasonic pressure waves from the second region to the first region through a window in the barrier.

15 39. The method of any of claims 34 to 38 wherein the barrier comprises a material having an acoustic impedance greater than that of water.

40. The method of any of claims 34 to 39 wherein the barrier comprises a material having an acoustic impedance of at least 12 x 106 kg/m2sec, for example at least 35 x

20 106 kg/m2sec.

41. The method of any of claims 34 to 40 wherein the liquid held in the second region is different to the liquid held in the first region.

25 42. The method of any of claims 34 to 41 wherein the ultrasonic energy is delivered to the products by at least one ultrasonic transducer coupled to a wall of the tank inside the tank.

43. The method of claim 42 comprising a plurality of ultrasonic transducers arranged

30 along the flowpath.

44. The method of claim 43 wherein the plurality of ultrasonic transducers are phase linked and/or synchronised.

35 45. The method of claim 43 or 44, as dependent on claim 38, or any claim dependent

27 07 17 thereon, wherein the barrier comprises a respective window for each ultrasonic transducer.

46. The method of claim 45 wherein each respective window is acoustically insulated

5 from the other windows.

47. The method of claim 38, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than the wavelength of ultrasonic pressure waves produced by the ultrasonic transducer.

io

48. The method of claim 38, or any claim dependent thereon, wherein the distance between the at least one window and the ultrasonic transducer is greater than 50mm, preferably 63 mm.

15 49. The method of any of claims 34 to 48 further comprising transferring liquid from the tank comprising the barrier separating the two regions to a reservoir, and heating the liquid in the reservoir to a temperature selected to disinfect the microorganisms forced off the products into the liquid.

20 50. The method of claim 49 comprising heating the liquid in the reservoir to a higher temperature than the tank.

51. The method of claim 49 or 50 comprising retaining the liquid in the reservoir for longer than in the tank, for example retaining the liquid in the reservoir for less than 5 s,

25 and in the reservoir for at least 30 s.

52. The method of claim 51 wherein the dwell time and temperature of the liquid in the reservoir are selected to disinfect the microorganisms forced off the products into the liquid, for example so that the liquid remains in the reservoir at a temperature of at least

30 75°C for at least 30 s.

53. The method of any of claims 49 to 52 comprising slowing the flow of liquid through the reservoir via a baffle arranged to encourage the liquid to stratify.

35 54. The method of any of claims 49 to 53 wherein the tank is inside the reservoir.

27 07 17

55. The method of any of claims 49 to 54 further comprising carrying the product through the tank via a conveyor.

5 56. The method of any of claims 49 to 55 comprising heating the liquid to the selected temperature with at least one of a heater and a heat exchanger.

57. The method of any of claims 49 to 56 comprising recirculating the liquid.

io 58. The method of claim 57 further comprising cooling the recirculated liquid.

59. The method of any of claims 49 to 58 comprising heating the liquid in the reservoir to at least 75°C.

15 60. The method of any of claims 49 to 49 wherein the reservoir is insulated to inhibit heat loss from the liquid.

61. The method of claim 57 or any claim dependent thereon comprising filtering the recirculated liquid.

62. The method of any of claims 34 to 61 further comprising driving the at least one ultrasonic transducer with an ultrasonic power oscillator coupled to the at least one ultrasonic transducer.

25 63. The method of claim 55, or any claim dependent thereon, comprising carrying the product through the liquid at a depth coinciding with the centre of the at least one ultrasonic transducer.

64. The method of any of claims 34 to 63 wherein the liquid is water.