The invention relates to a tray for use in food processing, and associated methods that are of benefit in food processing.

The invention is exemplified herein by reference to the processing of cold-processed fish products such as marinated and/or smoked salmon. However the invention is not limited to the preparation of fish products, and may readily be employed in processing e.g. of certain meat products such as cold-cured beef and pork products, dried meat products, tofu and similar curd-derived products, meat and non-meat sausages, cheeses, various plant-derived food products including but not limited to cold smoked plant foods and other food products as explained below.

More generally the invention concerns a tray and related methods that are of benefit in food production processes other than cooking. Such processes include but are not limited to smoking, marinating, oiling, seasoning, pasteurizing, freezing and thawing.

The term "meat" as used herein refers to edible animal flesh or organs including but not limited to fish meat; red meat such as beef and pork; gastropods (especially marine and freshwater gastropods); bivalves; cephalopod meat; and crustaceans or meat obtained from crustaceans.

The invention is of primary benefit in the processing of food for human consumption, although it may also provide advantages in the processing of foods for animal consumption.

The production and consumption of, in particular, cold-processed fish meat products have undergone generally continuous growth since the introduction of large-scale commercial marine farms starting in the 1970's. Nowadays the production of cold- processed fin fish products is a very substantial industry, with farming of fish contributing significantly to the economies of several countries including Chile, Canada, Norway, Scotland and the Faroe Islands.

Large-scale fish processing factories are located conveniently for the fish production industry, e.g. in or near to the main fish-landing ports, and/or adjacent logistics infrastructure and/or in locations where labour is available at acceptable costs in such countries. Such factories in many cases carry out processes that are derived from traditional marine product preserving and flavouring techniques such as salting, brining, marinating and smoking as well as slicing of whole fish into fillets for subsequent retail packaging and during which bones and fins etc. are removed.

The raw material in the form of farmed salmon for processing (e.g. as cold-smoked and marinated salmon) normally is delivered to a factory categorised in weight bands within the range 2-9kg. A primary objective of breeding is to target a fish weight of 3- 7kg, including the head of the fish. A preferred weight range is 4-6kg, which is optimal for the breeder with respect to the yield by weight and in payroll costs. Fish weights in this range also provide the fewest irregular slices in the production process. Irregular slice sizes are a significant problem in the industry, as explained herein.

Typical weight categorisation bands for salmon delivered from the breeder are e.g. ranges of 3-4kg, 4-5kg and 5-6kg. The fact that salmon, as a natural product, grows to different individual sizes causes multiple challenges in the production process. Until now the fish processing industry has not focused on addressing or remedying these challenges.

A typical sequence of processing steps for producing smoked salmon in a factory is:

1. Receipt of fresh whole gutted salmon from a breeder;

2. Washing, removal of mucus and surface bacteria;

3. Slicing of whole fish into fillets, during which bones and fins etc. are removed;

4. Peeling and rinsing of the (typically skinless) fillets;

5. Wet salting and/or dry salting of the fillets, either mechanically or manually;

5a. Placing of the fillets on steel gratings in weight amounts of up to 15-18kg of fish meat per grating, which in addition to the grating weight (6 -7kg) gives a total weight per grating of 21-25kg;

5b. Placing of the gratings on carts or trolleys capable of accommodating approximately 22 gratings giving rise to a total weight of 460-550 kg plus the weight of the cart;

6 Permitting maturing of the salmon in a cold store for a minimum of 6-8 hours; 6a. Drying of the salmon and then smoking for 6-8 hours at approximately 26°C;

6b. Cooling of the salmon in a cold room immediately after the smoking process has ended;

6c. Transporting of the salmon to a freezer the temperature in which is determined by how the salmon is to be sliced, with typical temperatures being from 0 to minus 5°C or minus 8 to minus 12°C;

6d. Removal from the steel grating of the frozen salmon followed by slicing;

6e. Packaging of the salmon according to weight;

7. Sealing of the packages using vacuum, modified-atmosphere gas or skin pack machinery;

8. Labelling, packaging, cold storage and/or refrigerated shipping of the completed packages.

During the salting step (Step 5) the fillets are placed on a belt. The lack of fixation of the fillets on the belt means they can move and/or settle. This leads to inconsistent and/or incomplete salting and is a cause of variability of the output of the production process, as further explained below.

The weight of the trolley and grates (Steps 5a and 5b) even when the latter are empty of fillets amounts to about 230 kg in a typical case. Step 6e takes place at a weighing/packing station that is manned and where the product is weighed and packed in bulk. The packaging step can be done semi- automatically but owing in part to slice size variations, many of the packages that are semi-automatically packaged subsequently have to be manually weighed, corrected and adjusted.

During the packaging stage slices of fish product resulting from Step 6d typically are placed on a sheet of foiled cardboard or foam. The size of the sheet will vary according to the weight requirement of the retail packaging. It is desirable that slices of the fish product generally match the dimensions of the packaging in which it is to be sold to customers.

As an example a typical packaging sheet width is 14 - 17 cm, yet the widths of the fish slices may range from 12 cm to 28 cm due to the raw material being a natural product with size variations both from one fillet to another and within each fillet, as further explained herein. Clearly this variability may lead to significant wastage of fish meat, either because of a need to trim the slices resulting from Step 6d to fit the packaging sheet or because the product is a "premium" one sold on the basis of its uniformity, and in which under-sized slices are not acceptable.

The steel gratings used in the foregoing process are disadvantageous in several respects, in terms of hygiene, non-uniformity of the slices produced, ease of use and cost. As explained further herein, one significant area of concern is adherence of proteins from the food product being prepared to the stainless steel of the gratings.

A primary drawback in this regard is that the gratings are difficult to clean after use. This is partly because of their size, which determines that they have to be cleaned in a specialised washing cabin.

In the existing art the carts referred to in Step 5b above are conveyed into the washing cabin after completion of a processing cycle, with all the contaminated gratings in situ. This creates a significant cleaning burden because it is as a result hard to ensure that all meat/protein residues are removed during the cleaning process. As is well recognized however it is very important from the standpoints of hygiene and product safety to ensure that the gratings are fully decontaminated between processing cycles.

The washing cabins are large structures measuring 110 x 100 x 200 cm. The temperature of the washing water is 70 - 80°C which gives rise to a significant energy overhead to operate the cabins. It is necessary to add costly and/or potentially environmentally hazardous chemicals in order to try and minimise the risk of residual contamination of the gratings and to avoid contaminant or residue build-up in the cabins. The washing cabins are very expensive to buy, costing typically €200000 or more. Further notwithstanding prior art attempts to recycle the water they use, the washing cabins are expensive to operate due to high temperatures and large amounts of water used in the washing process. Secondly, the gratings do not include any features that constrain the fish fillets after they are placed on them. The gratings therefore do nothing to prevent, and often exacerbate, the variability of the dimensions of the slices of fish product that are produced at Step 6d.

This variability arises chiefly because the fillets are not of constant cross-section along their lengths, so (for instance) a slice taken from near the tail end of the fillet will be smaller than a slice cut from nearer the lengthwise mid-point of the fillet. A slice cut from the tail region of the fillet may be too small to be packed, meaning it may be wasted.

Equally, part of the fillet near the belly of the fish may be too wide to produce slices of the desired dimensions. In such a situation it is known to fold the belly meat (i.e. what remains of the ventral muscle after the various preparation steps) under the remainder of the fillet when placing the fillet on the grating; but this is a manual, time-consuming process that itself may introduce variability.

The variations in fillet cross-section dimensions also may mean that the fillets may be processed unevenly. When for example the principal processing step involves salting of the fillet this can be critical to product acceptability. If part of the fillet by reason of its width or thickness receives too little salt its keeping qualities become adversely affected, thereby increasing the risk of survival of harmful bacteria or parasites. If on the other hand because of diminished dimensions part of the fillet receives an excess of salt this renders the slices from that part of the fillet unpalatable and hence of little or no commercial value.

The application of a processing medium such as salt in many instances is carried out manually or at best using only a semi-automated process, in part because automated processes are not capable of accommodating the fillet dimension variability explained above unless very expensive machinery is employed.

Furthermore the gratings are such that the fillets can move during processing. Surface proteins on fillets that contact one another as a result of movement can cause the fillets to stick to one another in a manner leading to waste when they are pulled apart. Also many of the known processes involve freezing the fillets prior to slicing as a final stage of processing. Fillets that are in contact with one another at such a time may be very hard to separate and may suffer damage in the separation process. The damaged slices that can result are of low commercial value and may have to be thrown away. Similarly as mentioned proteins on or produced from the fillets tend to stick to the gratings. During the separation process the fillets may be damaged as the adhered proteins cause them to stick to the gratings.

Contact of the fillets during processing also can result in uneven or incomplete exposure of parts of the fillets to the processing medium such as salt or marinade as a result of part of a fillet being shielded by another fillet. The proteins and/or moisture in the fillets moreover can cause meat residues to adhere firmly to the bars of the gratings, and these residues can be difficult to remove during cleaning in the cleaning cabins.

The gratings in current use weigh about 6 - 7 kg each. Repeated manual handling of these represents an injury risk to fish factory employees, especially when attempts are made to lift multiple gratings at a time. The gratings cost about €60 each and for employee safety reasons have to be discarded if any of the welded joints forming them should fail. It is clear from the foregoing that there is a strong need for an improvement on the prior art steel gratings used in fish processing and processing of other types of meat.

According to the invention in a first broad aspect there is provided a tray for use in food processing comprising a base member defining an in-use upwardly facing surface; and a plurality of compartment walls that extend upwardly from the upwardly facing surface, the tray including within the perimeter of the upwardly facing surface a series of compartments one or more of which are non-terminative compartments of the series, that are each at least partly bounded by a respective pair of the plurality of compartment walls and a portion of the upwardly facing surface, and that are open on an upper side for the placing therein of a food product to be processed in the tray, characterized in that the base member includes formed passing therethrough a plurality of perforations extending over the whole area of the base member whereby the base member in the compartments is permeable to fluid. As used herein "upwardly" and derivative or related terms refers to the orientation of the tray when in normal use to support meat products, i.e. with the base member horizontal or largely horizontal.

Such a tray offers numerous advantages over the prior art gratings. Among these is that the trays are easier to clean than the metal gratings. Moreover the presence of the compartments means that a greater density of fish meat, in the form of fillets, may be carried per unit area of the base member than is the case when using the traditional gratings described above. As explained, the gratings do not constrain the fish, with the result that only a relatively low packing density of fish meat may be achieved.

A very significant aspect is that the ability to constrain the fillets in the trays leads to more consistent application of media such as salt, marinade and smoke; and also improves the consistency of slices of the fillet as further explained herein. Furthermore the fillets are placed in the trays at an early stage in the processing of the fish, shortly after skinning and boning. This means that the overall amount of handling of the fillets by humans is minimized, in turn reducing the risk of e.g. bacterial contamination.

The improved packing density of the trays of the invention means that they may be made of smaller width and length dimensions than the gratings while still being able to accommodate economically acceptable quantities of fish meat. As a result the trays may be made in sizes that readily fit in to standard commercial industrial washing machines. These are smaller than the washing cabins described above. They are cheaper to buy and cheaper to operate; and since the washing chamber of a standard industrial washing machine is smaller than the chamber of a washing cabin it is easier to heat the washing water to a temperature that results in effective cleaning of the trays.

The reduced size of the tray compared with metal gratings inherently means that the tray is lighter, and hence easier/safer to handle manually, than the gratings. Furthermore as explained herein the tray is suitable for manufacture from plastics materials. This further leads to weight savings compared with the prior art gratings.

The perforations beneficially permit a processing medium of the kinds exemplified herein effectively and evenly to surround and contact or coat a food fillet or slab in the tray during processing. Preferably the tray additionally may include one or more first outer walls that extend upwardly from the base member and each define with one of the plurality of compartment walls and a portion of the upwardly facing surface a respective terminative compartment of the series that is open on an upper side for the placing therein of a food product to be processed in the tray.

The first outer walls define one or, more typically, two further, terminative compartments extending along either side of the series of non-terminative compartments defined by the compartment walls. The further compartments terminate the series of compartments and are labelled as "terminative" herein for this reason. The first outer walls in addition to partially defining these compartments beneficially confer rigidity on the tray, and assist with location of a further tray when it is required to stack multiple empty trays one on top of another.

Further advantageously at least one said first outer wall may include formed therein or thereon a recess, perforation or handle permitting manual lifting of the tray. Such a feature assists in the handling of the tray in a factory environment. In practical embodiments two of the first outer walls would include such features aiding lifting, whereby the tray may readily be manually gripped on two opposite sides and easily lifted without tilting.

Forming the tray with readily visible gripping handles or gripping apertures as indicated means that the tendency of factory workers directly to handle the fillets is reduced, with the consequence that the fillets are isolated from hand-borne contaminants such as bacteria.

Preferably the tray may include one or more second outer walls that extend upwardly from the base member and each close off, in the sense of preventing escape of food products in the compartments, an opening in at least one of the non-terminative and/or one of the terminative compartments of the series of compartments. The opening closed off by the second outer walls typically is in each instance at the end of a compartment. The one or more second outer walls thereby contain the fish fillets (or other food products if the tray is used otherwise than for fish processing) longitudinally in the compartments and also assist in providing the requisite degree of rigidity of the trays. In this regard the trays are intended to be sufficiently rigid to perform supporting and containing functions as explained herein, while being flexible in a manner that assists in the removal of frozen fillets as occurs in Step 6d of the method explained above.

Conveniently the base member may be an essentially planar rectangle and the plurality of compartment walls may extend parallel to one another and to the minor sides of the rectangle. In such a configuration the compartment walls are spaced from one another along the major length of the rectangle.

This arrangement gives rise to a series of cuboidal, open-topped compartments that are rectangular in plan view. Compartments of this kind are suited for the processing of fish fillets and indeed a range of other food products. This is especially so when considering the potentially competing requirements in fish processing of adequate strength of the tray to support a heavy mass of fish meat while permitting the circulation of air or smoke and the even application of salt or other media. However in other embodiments the walls of the tray may be shaped and/or positioned to give rise to other compartment shapes if desired.

As a non-limiting example in this regard the compartments may in an alternative embodiment be defined as an array of compartments that each are for instance square when viewed in plan from above. As explained in the preferred embodiment of the tray employed for fish processing the compartments may define a single series extending along the base member as illustrated in the figures hereof; but in other embodiments the optional inclusion of additional, intermediate compartment walls may give rise to e.g. a grid layout comprising multiple rows and columns. The compartments in such an embodiment may be rectangular or square in plan view, or as mentioned may adopt other shapes, depending on the precise requirement.

Preferably the plurality of compartment walls are equally spaced from one another along the major length of the rectangle. Also preferably at least one said first outer wall extends parallel to the minor sides of the rectangle. These features give rise to a series of compartments that are each of the same width and shape. However in some instances it may be desirable for example for the compartments not all to be of the same width, in which case unequal spacings of at least one pair of the compartment walls may feature.

Similarly in preferred embodiments of the invention the second outer walls are positioned such that the lengths of the compartments of the series are all the same; but again this need not necessarily be the case. Hence it is possible for the tray of the invention to include compartments of differing lengths as determined by the shapes, orientations and positions of the walls that with the base member define the boundary of the compartment. Such aspects of the design of the walls may be varied significantly within the scope of the invention and in particular the walls need not necessarily be straight, continuous or mutually parallel. These possibilities notwithstanding, it is most probable that in preferred embodiments at least one said first outer wall and at least one said second outer wall of the tray intersect one another at right angles. In practical embodiments the perforations in the base member adopt a grid pattern. The perforations may adopt any of a range of shapes including circles, squares, other geometric shapes and irregular shapes. Mixtures of perforation shapes are possible within one and the same tray; or the shapes may be uniform within a tray. Rounded corner profiles as explained below preferably are included at any corners of the perforations in order to maximize the ability to clean the tray. The pattern, number and size(s) of the perforations are chosen so as to optimize the permeation of media such as salt, marinade, preservative and smoke while helping to confer a desired combination of stiffness and flexibility as explained herein.

Preferably at least one of the compartment walls includes one or more cut-outs or recesses that confer flexibility on the tray. Such cut-outs or recesses in preferred embodiments take the form of notches formed in the upper edges of the compartment walls; but in other embodiments different features may be provided that confer the requisite degree of flexibility, as explained herein, on the tray as a whole.

In more detail, preferably the one or more second outer walls and the one or more cut-outs or recesses interact co-operatively to confer flexibility on the tray when it is subject to torsion about an axis extending in a first direction and not when it is subject to torsion about an axis extending in a second direction that is essentially orthogonal to the first direction. This arrangement advantageously makes it easy to remove frozen fillets or slabs from the tray by twisting it about a first axis that is parallel to one of the dimensions of the base member, while conferring sufficient stiffness on the tray as to enable its handling when loaded with fillets or slabs.

Conveniently one or more of the cut-outs or perforations formed in the tray defines one or more corners having a rounded profile. This feature assists significantly in cleaning of the tray since rounded corners make it less likely than in the prior art that meat residues and/or proteins may remain adhered to the trays.

In practice therefore the tray will include a large number of rounded-profile corners as described, whether forming parts of notches in the dividing walls or forming parts of perforations formed in the material of the tray. In particularly preferred embodiments all the corners forming parts of perforations or cut-outs will adopt the indicated rounded profiles, thereby minimising as far as possible the chance that meat residue or protein adherence will be problematic at the cleaning stage.

The conventional welded metal construction of prior art gratings means it is impossible in designs of them to eliminate sharply angled corners in the grating structure. As a result the cleaning ability of the prior art gratings is inherently considerably worse than that of the tray defined herein.

Conveniently at least one said second outer wall includes extending therethrough one or more recesses and/or perforations. Such features further help to confer adequate flexibility and also help permit a cleaning fluid such as detergent-containing water to reach all parts of the tray during cleaning.

In preferred embodiments the parts of which are formed integrally with one another as a single item. This means that the tray may readily be manufactured e.g. by moulding at low cost from a polymer material such as polypropylene (PP) or high- density polyethylene (HDPE). Other food grade, preferably recyclable, plastics materials are also possible.

Such materials confer lightness on the tray and are easier to clean than the steel of the prior art gratings. This is not least because fish meat/proteins is less prone to adhering to PP and HDPE; and moreover some grades of these materials are suitable for being sterilized using ultraviolet (UV) light without degrading unacceptably.

Conveniently one or more part of the tray optionally may include one or more reinforcing ribs. Such features also assist in conferring the preferred balance of stiffness and flexibility, and in particular stiffness in selected loading modes (e.g. corresponding to manual carrying) that are useful for supporting products in the trays while permitting flexibility in other modes such as twisting to release frozen fillets or slabs. In a particularly convenient aspect at least one of the compartments of the series is capable of defining, in combination with a compartment of a series of a further tray according to the invention, an essentially closed-sided compartment when the further tray is placed in an inverted orientation so as to overlie and contact the at least one said compartment. This facility permits a fillet or slab in a tray to be contained while the tray is inverted. Consequently the application of a processing medium may be achieved with significantly greater uniformity than has been possible up to now. This in turn is because the prior art gratings do not prevent the food product from falling off in the event of inversion.

Conveniently the tray is rectangular in plan view, has a width in the approximate range 45 - 60 cm and has a length in the approximate range 90 - 100 cm. Such dimensions are particularly suitable to permit the tray to be cleaned in a standard industrial washing machine. A particularly preferred width x length dimension is 60 cm x 100 cm; although the tray can be manufactured to almost any size that suits a user's production set-up and machinery, and the food product requiring processing.

The tray disclosed herein further is advantageous because the various features mentioned individually or collectively contribute to suitability of the tray for handling in automated and/or robotic machinery.

According to a further aspect of the invention there is provided method of processing a food product comprising (a) placing an elongate food fillet or slab in at least one compartment of a tray as defined herein, the fillet or slab being wider over at least part of its length than the width of the compartment whereby the compartment laterally compresses the fillet or slab and renders its cross-section approximately uniform over a major part of the length of the fillet or slab; (b) exposing the tray and fillet or slab to a processing medium whereby the processing medium affects at least a surface layer of the fillet or slab in the compartment; (c) removing the fillet or slab from the compartment; and (d) slicing the fillet or slab transversely to its longitudinal direction to give rise to a plurality of essentially uniform food product slices.

A very significant benefit of the tray of the invention therefore is the rendering of a width-varying food product substantially of uniform width over most of its length. This in turn means that slices cut from the slab or fillet that undergoes treatment in the tray are of substantially the same dimensions regardless of the part of the slab/fillet from which they originate. This is likely to represent a major advance for certain food product manufacturers, because the number of unacceptably small slices per fillet or slab will be substantially reduced; and the occurrence of wastage caused by excessive fillet width also will be reduced.

Preferably the fillet or slab is a fish fillet or a red meat fillet, although as mentioned other food types also may be processed using the method and tray of the invention.

In view of this preferably the processing medium may include one or more selected from the list including salt, sugar, smoke (especially wood smoke or charcoal smoke), water, water vapour, steam, brine, culinary sauce, liquid and/or powder and/or granular seasoning, one or more herbs, one or more spices, culinary oil, low-humidity air, humid air, low-temperature air, heated air, food-grade nitrite- or nitrate-containing compounds and marinade.

Optionally the method includes one or more of, before and/or after Step (b), (bl) chilling the fillet or slab in the compartment; and/or (b2) drying the fillet or slab in the compartment; and/or (b3) freezing the fillet or slab in the compartment. If desired yet further intermediate seps may be completed as part of the method.

An optional refinement of the method is the inclusion of a step of (e) packaging the food product slices in a preserving package. As used herein the term "preserving package" refers to any packaging that is suitable for prolonging the edible nature of the food product produced in accordance with the method hereof and/or produced using a tray as defined herein. A great variety of packaging types are known. It will be apparent to the person of skill in the art which packaging types are suitable; and for this reason the precise details of packaging products are not discussed in detail herein.

Optionally the method includes steps of (f) placing a further tray as defined herein in an inverted orientation so as to overlie the fillet or slab in a manner defining an essentially closed-sided compartment; and (g) inverting the thus-positioned trays and the fillet or slab in the compartment in a processing medium. This aspect of the method may include securing the resulting pair of trays one to the other using fastenings such as but not limited to clips, bands, string or twine or through the operation of processing machinery in holding the pair of trays in contact with one another.

The disclosure hereof further extends to a method of cleaning a tray as defined herein following its use in processing of a food product, the cleaning method including the steps of placing the tray in a standard industrial washing machine and operating the washing machine in order to clean the tray.

The cleaning method optionally may include the additional step of exposing the tray to ultraviolet light. This step is of potential benefit when as is preferred the tray is made from certain grades of PP or HDPE. UV treatment of the prior art gratings in contrast is believed to be unlikely to bring about the same degree of sterilisation.

The invention also extends to use of a tray as defined herein in the processing of a food product.

Such use may include transporting one or more trays as defined herein to, from or within a food processing factory and/or storing one or more such trays in a food processing factory.

Use of the tray as defined herein optionally may include including the step of stacking two or more trays each as defined herein one partially inside another to define a vertical stack of the trays.

The invention additionally extends to food product manufactured by a method as defined herein or resulting from use of a tray also as specified herein.

More generally the invention provides a means, methods and related products that address or at least ameliorate one or more drawbacks of prior art food processing, especially but not exclusively in the cold processing of fish.

There now follows a description of a preferred embodiment of the invention, by way of non-limiting example, with reference being made to the accompanying drawings in which:

Figures la to le show variously in plan and cross-sectional view some characteristics of prior art cold processing of a salmon fillet cut from the belly and tail portions of a fish;

Figures 2a to 2d are a series of plan views showing a selection of ways in which sliced, smoked salmon may be placed on boards as part of a packaging step;

Figure 3 is a perspective view of a tray as disclosed herein and that is suitable for use in methods as disclosed herein; and

Figure 4 is a plan view from above of the tray of Figure 3. Figures 1 and 2 hereof illustrate some aspects of, and hence the problems that arise in, use of the prior art gratings used in the cold processing of fish products such as smoked, marinated, salted, brined or otherwise treated fish slices.

Figure la shows a pair A, B of fillets that result from Step 3 of the prior art processing method, described above, carried out on a fish in a processing factory. As mentioned if the fish is of ideal weight it weighs approximately 4 - 6 kg before processing. Following removal of the head, tail, bones, fins and other unwanted parts each fillet might in a typical case weigh about 1.5 - 2.5 kg.

The head end H of each fillet A, B is apparent in Figure la as a relatively wide portion viewed in plan as shown. The tail end T of each fillet is considerably narrower in the transverse direction. The approximate plan view longitudinal centre line of the fillets is shown in dotted line form in the figure.

Between the head end H and tail T each fillet is chiefly constituted by the meat of the dorsal muscle and ventral muscle of the salmon. The belly of the fish is removed as part of Step 3 of the prior art process, leaving a flap F of ventral muscle meat extending from each fillet A, B laterally from the dorsal muscle meat.

Figure lb shows an ideal fillet transverse cross-section that as signified in the figure is approximately 14 cm wide. This width dimension gives rise to slices of smoked fish cut from the fillet in a transverse direction that are readily suitable for packaging and are widely accepted for sale and consumption.

As shown in Figure lc however, which illustrates the transverse cross-section of fillet B of Figure la in the vicinity of the ventral muscle meat F, the ventral muscle meat remaining after removal of the fish belly and longitudinal cutting to create two mirror image fillets A, B extends significantly further, in the transverse direction, than the ideal 14 cm width of Figure lb. In the illustrated example the maximum width of the fillet in the illustrated zone is 22 cm, meaning among other things that the slices cut at this location are too wide for the packaging boards preferred in the industry. A conventional attempt to address this drawback involves folding by hand of the ventral muscle meat F under the dorsal muscle meat before the cutting of slices occurs. The result of this is shown in cross-sectional view in Figure Id. If done correctly the ventral muscle meat folding step gives rise to a cross-section width of 14 cm as is desired; but is associated with several remaining disadvantages. These include increased handling of the fillets, with concomitant increases in bacterial contamination risks, during the folding stage; inconsistencies of cross-sections resulting from the manual nature of the folding step; and delays in the processing of the fillets while the folding is undertaken on a fillet-by-fillet basis.

Furthermore as shown by Figure le, which is a plan view from above of the fillet A after the folding step, although in the vicinity of the dorsal and ventral muscle meat the width of the fillet is more consistent than before folding occurs the ventral meat folding step does not alter the dimensions of the fillet near the tail end T. As a consequence the width of the fillet remains significantly less in this region than in the folded part nearer the head end H.

Slices cut transversely from the tail portion T even after folding of the ventral muscle meat may be too small to be acceptable for packaging and may suffer from excess salt and smoke penetration. Consequently such slices may be treated as waste or if packed may be of reduced value compared with the ideal slices described above.

As described above, at Step 5a of the conventional cold processing method the fish fillets, after having undergone some pre-processing steps, are placed on the gratings. At this stage notwithstanding that the fish may have been transported to the processing factory in ice boxes, the fillets are essentially unfrozen.

When a fish is placed on the grating it is flexible and tends to sag under its self-weight. This can exacerbate the slice dimension variation from one part of the fish to another; and may cause adjacent fish to contact one another. As explained, this also is associated with disadvantages in terms of product damage, uneven application of processing media, adherence to the gratings and waste.

Even if the fillets do not sag appreciably (e.g. because they are semi-frozen) the gratings do not prevent their movement during handling and processing. As a result the fillets may contact one another giving rise to the contact problems explained above.

Moreover even if the foregoing problems did not arise, as may be the situation when handling foods that are not as variable as fresh fin fish, as explained there are various cleaning, difficulty of handling, cost, weight and safety drawbacks of the prior art gratings. Referring now to Figures 3 and 4 there is shown a tray 10 according to the invention that seeks to solve or at least ameliorate one or more of the problems of the prior art. The tray 10 is intended for use to support and contain a plurality of food products such as a plurality of fish fillets in side-by-side adjacent compartments 11, 12. The compartments 11, 12 extend in a series along the length of the tray 10. To this end the tray 10 includes a base member 13 that is an essentially planar, rectangular sheet defining an in-use upwardly facing surface 14; and a plurality of compartment walls 16.

The compartment walls 16 are formed so as to extend upwardly from the upwardly facing surface in a mutually spaced apart series that extends along the major dimension of the rectangle defined by the base member. The compartment walls 16 are located so as to lie within the perimeter of this rectangle with the result that each mutually adjacent pair of the compartment walls 16 defines, in combination with the base member 13, a respective compartment 11.

The compartments 11 themselves form a series that extends in the direction of the major dimension of the rectangular shape of the base member, with the individual compartments also being rectangular in plan view and having their major dimension extending transversely to the direction in which the series extends. The compartments 11 are identified as "non-terminative" herein simply to signify that they do not themselves terminate the series and instead exist intermediate the ends of the series.

Each compartment 11 is as illustrated open on an upper side. This permits the placing in each compartment of a food product such as a fish fillet during processing as described herein. The tray 10 includes extending parallel to the compartment walls 16 at each end of the base member 13 a respective first outer wall 17. Each of the first outer walls 17 extends upwardly from the base member 13 when the base member 13 is horizontal.

The first outer walls 17, which are optional in the most rudimentary versions of the invention and are preferred in the majority of embodiments, define with the next adjacent compartment wall 16 in the direction towards the centre of the base member 13 a respective further compartment 12. This is identified as a "terminative" compartment herein because it terminates the series of compartments extending along the tray 10. The terminative compartments 12 in other respects are functionally the same as the non-terminative compartments 11.

The terminative compartments 12 in the embodiment of Figure 1 extend parallel to and are of the same dimensions as the non-terminative compartments 11 and in like manner to those compartments are open along an upper side to permit the placing therein of a food product that is to undergo processing in the tray 10.

The terminative compartments 12 may in alternative embodiments be of different dimensions to the non-terminative compartments 11. In particular the widths of the terminative compartments 12 may differ from those of the non-terminative compartments 11. Moreover in versions of the tray 10 intended for specialist food processing as explained herein the shapes of the terminative compartments 12 may differ from those of the non-terminative compartments 11. Furthermore it is not essential that the non-terminative compartments 11 are all of the same shape and size. On the contrary the shapes and sizes of the non-terminative components also may be varied to cater for specific food processing requirements.

However it is anticipated that the majority of trays 10 according to the invention will be manufactured for use in the fish processing industry and in connection with such usage it is expected that the compartments 11, 12 in an individual tray 10 all will be of the same size and shape and will extend parallel to one another, as illustrated, transversely from one side of the tray 10 to the other.

The number of compartment walls 16 preferably is selected so that the number of terminative and non-terminative compartments 12, 11 is even. This is primarily because two fillets are normally prepared from each fish at Step 3 of the process summarised above. The presence of an even number of compartments 11, 12 minimises the chance that a fillet may become wasted because there is no tray compartment available in which to place it to undergo processing.

As is apparent from Figures 1 and 2 the first outer walls 17 each include formed therein a respective, central handgrip aperture 18 formed extending through a handgrip tab 19 that extends upwardly from the upper edge of each first outer wall. This is of a per se familiar kind in food tray design and facilitates ready manual handling of the tray 10 both when it is empty and when it is carrying a full load of fillets. Other ways of providing manual gripping features are also possible and are within the scope of the invention. It is not necessary to adopt the handgrip aperture and tab combination illustrated. Handgrip features generally are optional but desirable in embodiments of the invention.

The tray 10 additionally is formed to include extending longitudinally along each major edge of the rectangle defined by the base member 13 a respective second outer wall 21. Each of the second outer walls 21 extends upwardly from the base member 13 when the base member 13 is horizontal. The second outer walls 21 intersect the compartment walls 16 and the first outer walls 17 at right angles at the respective longitudinal ends of the compartments 11, 12. As a result the second outer walls 21 terminate the ends of the compartments 11, 12 that would be open but for the presence of the second outer walls 21.

It is clear from the foregoing description and Figures 3 and 4 that a fillet placed in a compartment 11, 12 of the tray will be constrained against side to side movement by at least one or, in the case of the compartments 11, two of the compartment walls 16 and, in the case of the compartments 12 by one of the compartment walls 16 and one of the first outer walls 17. The walls of the compartments 11, 12 separate the fillets and prevent them from contacting one another during processing.

Furthermore the width of each compartment 11,12 is such that the central, dorsal muscle/ventral muscle part of each fillet is laterally compressed by the compartment walls after placing therebetween. As a result some repositioning of the flesh of the flexible fillet occurs when the fillets are placed into the compartments and for a time thereafter, such that the dimensions of the part of the fillet corresponding to the fish tail are increased.

The width of the fillet near the tail end is less than that of the compartments 11, 12. As a result there is room for the tail meat to expand and settle to a wider dimension even though the dorsal muscle/ventral muscle region is laterally constrained. Consequently the slices produced from the tail parts of the fillet at Step 6d of the processing method are closer to the desired dimensions than in the prior art and hence are more likely to be of commercial value.

At the same time the fillet in its widest (belly) part is width-wise compressed with the result that the largest slices are within acceptable maximum width dimensions, with a significantly reduced need for trimming or folding and the associated product wastage. Overall therefore the effect of the compartments of the tray is to cause the cross- section of each fillet to become more uniform along the length of the fillet. This significantly reduces the amount of fish meat that is rejected as being of the wrong dimensions to be packed and sold.

As is apparent from Figures 3 and 4 the base member 13 is perforated by an array of through-going perforations 22. The purpose of the perforations 22 is to permit permeation from underneath of a processing medium, that may be of the kinds indicated herein, thoroughly around all parts of a food product such as a fish fillet in each compartment 11, 12. The perforations 22 also permit draining of excess processing medium, when this is in liquid, granular or powder form, applied from above the fillets.

In the illustrated embodiment to this end the perforations 22 are square, with the described rounded corners, when viewed in plan from above; but other perforation shapes such as but not limited to circles, other geometric shapes or irregular shapes may be provided.

The design of the perforations 22 in the illustrated base member 13 is intended to maximise the permeation of the processing medium. For this reason the whole area of the base member 13 is perforated, with the perforations 22 defining a reticulated grid pattern as illustrated and only relatively small lands of base member material between the perforations 22. The aim of this design is to equalize, as far as possible, the circulation of processing medium from underneath the food product and the unimpeded permeation that occurs via the open upper side of each compartment.

However in other arrangements, that are not specifically claimed herein, intended for specialised processing of food products it is possible for example for not all the area of the base member 13 to be perforated. This can give rise to for instance certain compartments 11, 12 the bases of which are unperforated; and/or compartments in which only part of the base region is perforated.

Near the intersections of the compartment walls 16 with the second outer walls each upstanding wall 16 includes a pair of optional cut-outs in the form of notches 23 extending downwardly from the upper edge of the wall 16 in a v shape. The purpose of the notches is to reduce the stiffness of the walls 16 and thereby permit limited manual flexing of the tray 10 about a torsional axis extending approximately between the handgrip apertures 18. This feature of the tray 10 allows a factory worker to twist the base member 13 and promote the releasing of fillets that are frozen in place (or otherwise retained) in the compartments 11, 12. The first outer walls 17 and the second outer walls 21 are comparatively rigid and act co-operatively at such a time to promote the desired torsion. However the notches (cut-outs) 23 do not appreciably reduce the stiffness of the tray 10 about an axis that is orthogonal to the described torsional axis. As a result the tray 10 retains sufficient rigidity to carry out its functions in supporting the fish fillets during processing. Although the v-shaped notches 23 are preferred from the standpoint of ease of manufacture of the tray 10, it is not mandatory to adopt this shape. Numerous alternative features, such as closed-sided perforations, may be employed. Moreover the notches 23 or equivalent features do not need to be provided in pairs, or in the locations indicated in the drawings, or at each end of each compartment wall 16, or in all the compartment walls 16. In consequence a high degree of adjustment over the stiffness performance of the tray 10 may be provided depending on the precise design adopted.

Each second outer wall 21 includes an optional series of through-going further perforations 24 as illustrated. The further perforations 24 in the illustrated embodiment are ovals of two different sizes and are arranged as two in-use horizontal rows as shown. The purposes of the further perforations 24 are to help promote good circulation of processing medium or air around food products in the compartments 11, 12; to lighten the tray 10 compared with a version including solid walls; and assist with the draining of washing fluid when the tray 10 is cleaned. In view of these functions it is apparent that the further perforations 24 may adopt a wide variety of alternative shapes and patterns to those illustrated. The further perforations 24 may be formed as notches or recesses in preference to the closed-sided oval shapes shown. Mixtures of different designs of the further perforations 24 are possible.

The notches or equivalent features formed in the tray in like manner to the apertures 22 have optional but preferred rounded corners at their in-use lowermost ends. These assist in the ability to clean the notch regions of the tray 10. It is preferred that the tray 10 is manufactured from PP or HDPE as mentioned; or from an alternative food grade material. PP and HDPE tend not to promote the growth of bacteria; may be cleaned using a variety of chemicals such as detergents and antibacterial agents; may be sterilized using ultraviolet light; are cheap; and are of low density, meaning the tray 10 weighs only a few tens of grammes. This compares very favourably with the mass of a prior art steel grating. Manufacture of the tray 10 from PP or HDPE furthermore lends itself to mass production by moulding. Especially when the tray 10 is made in this way the parts of the tray as described above are formed integrally with one another as a single item that does not require additional assembly after moulding. This means that the tray 10 can be produced in large numbers, very economically.

However as will be apparent to those of skill in the art it is also possible to manufacture the tray 10 by various other methods and using a variety of other materials; and all such variants lie within the scope of the invention.

The compartment walls 16, the first outer walls 17 and the second outer walls 21 are in the illustrated embodiment of Figures 3 - 4 shown including extending upwardly from the level of the upwardly facing surface 14 a series of reinforcing ribs 26 that protrude on the external surfaces of the walls. Such features may be desirable to reinforce the various walls and also to assist in removing a completed tray 10 from a mould tool during manufacture. However the arrangement, shape, thickness and number of the ribs shown in the figures is entirely exemplary. The ribs may be varied significantly within the scope of the invention, replaced by alternative features having a similar function or, in some cases, dispensed with altogether.

The various walls 16, 17 and 21 are in the illustrated embodiment shaped and dimensioned such that following placing of food products in one or more of the compartments 11, 12 it is possible to place a second tray, that is of the same or similar design to the illustrated tray 10, in an inverted orientation overlying the tray containing the food product(s). This causes the open upper side of each compartment 11, 12 to be closed in the sense of retaining the food product by the walls and base member defining a counterpart compartment in the further tray. The tray 10 and the inverted tray may then be temporarily secured to one another in this configuration, for example using clips that may be moulded or otherwise formed in the tray parts; bands such as elasticated bands or tension bands; string; or twine. Alternatively the trays may be pressed into contact with one another by moveable parts of processing machinery.

Following such securing the resulting two-tray assembly containing food products may be inverted as a whole and/or tumbled as part of the food production process, without any risk that the food product will fall out of the compartments. In turn this promotes even permeation of processing media onto and around the food products. This is particularly beneficial when the processing medium is or includes salt. As explained it is desirable for the application of salt to e.g. fish fillets to be completed as uniformly as possible, and the option to invert the fish fillets assists greatly in this regard.

As an alternative to securing two trays together as described it is possible to provide e.g. a sheet that may be secured so as to close off the open upper sides of the compartments 11, 12 when it is required to invert the food product. Such a sheet or similar component as would occur to the person of skill in the art may be secured in place in similar ways as described above. The sheet may be perforated over is area, may be perforated over part of its area or may be unperforated depending on the precise usage situation. If the sheet is perforated the variants on numbers, types, patterns and shapes of the perforations as described above may be employed in the sheet perforations.

One specific embodiment of the tray 10 is rectangular in plan view, has a width in the approximate range 45 - 55 cm and has a length in the approximate range 90 - 100 cm. However the invention is not limited to these dimensions and considerable variation is possible within its scope.

The invention also resides in a method of processing a food product comprising (a) placing an elongate food fillet or slab in at least one compartment of a tray 10 as described above, the fillet or slab being wider over at least part of its length than the width of the compartment whereby the compartment laterally compresses the fillet or slab and renders its cross-section approximately uniform over a major part of the length of the fillet or slab; (b) exposing the tray 10 and fillet or slab to a processing medium whereby the processing medium circulates around and/or permeates the fillet or slab thereby affecting at least a surface layer of the fillet or slab in the compartment; optionally (c) chilling or freezing the fillet or slab in the compartment; (d) following chilling or freezing, if carried out, removing the fillet or slab from the compartment; and (e) slicing the fillet or slab transversely to its longitudinal direction to give rise to a plurality of essentially uniform food (e.g. meat) product slices.

The possible processing media may vary significantly depending on the food product being processed and the intended non-cooking effect it is required to bring about. A non-exhaustive list of preferred processing media includes salt, sugar, smoke, water, water vapour, steam, brine, culinary sauce, liquid and/or powder and/or granular seasoning, one or more spices, culinary oil, low-humidity air, relatively humid air, low- temperature air, heated air, food-grade nitrite- or nitrate-containing compounds and marinade. The food product itself also may take a variety of forms and includes without limitation various marine products as listed herein; meat, vegetarian and vegan sausages; certain cheeses requiring e.g. coating in herbs, marinade or seasoning or requiring smoking; and non-marine meats or meat products that require drying, air curing, smoking, marinating or coating.

Methods within the scope of the disclosure hereof optionally may further include one or more of, before or after Step (b), (bl) chilling the fillet or slab in the compartment; and/or (b2) drying the fillet or slab in the compartment; and/or freezing the fillet or slab in the compartment. Furthermore methods within the scope of the disclosure may include, without limitation, a step of (f) packaging the food product slices in a preserving package. Such packaging may if desired include the addition of one or more preservatives, antibacterial compounds and/or so-called "modified atmosphere" packaging gas within the preserving package.

Figure 2 illustrates in schematic plan view certain non-limiting packaging board examples, including width and length dimensions, that are in use in the cold fish processing industry. Figure 2a shows a 14 cm x 16 cm board that accommodates four slices of fish; Figure 2b a 12 cm x 12 cm board that accommodates three smaller slices of fish; Figure 2c a 14 cm x 32 cm board that accommodates seven or eight slices of fish; and Figure 2d a 12 cm x 26 cm board that accommodates seven smaller slices of fish. It will be apparent from these figures that the tray and methods of the invention can give rise to consistently sized fish slices that are ideally suited for packaging on such boards, with much less need to accommodate variations than in the prior art. Hence the slices cut from the dorsal muscle/ventral muscle section of the fillets are consistently of widths suitable for packing on the 14 cm-wide boards shown, with the longer boards giving rise to larger packages than the smaller ones; and the slices from the tail section are consistently of widths suitable for packing on the 12 cm boards, again with the overall mass of the package being determined by the lengths of the boards.

In other words the improvements in slice width consistency brought about by the invention mean that slice variability is virtually eliminated. As a result a much greater percentage of the fish meat may be produced in slice sizes that are suitable for packing on a much smaller inventory of board sizes than might have been the case in the prior art. As explained the methods of the invention also optionally may include steps of (g) placing a further tray according to any of Claims 1 to 18 in an inverted orientation so as to overlie the fillet or slab in a manner defining an essentially closed-sided compartment; and (h) inverting the thus-positioned trays and the fillet or slab in the compartment in a processing medium.

Also as explained the tray 10 is considerably easier to clean effectively than the steel gratings presently in use. This is in part because the space-efficiency of the tray 10 allows a higher density loading with food products, meaning in turn that for the processing of a specific mass of food product a tray may be used that is much smaller than the gratings. Such a reduced-size tray may be cleaned at considerably reduced cost, compared with the present techniques, in a standard industrial washing machine that is cheaper to buy and operate than a washing cabin. The invention includes such cleaning of one or more tray 10 and, optionally, ultraviolet light treatment in a bacteria- killing step. In addition as explained the rounded corners of the various perforations and cutouts significantly improves the ability to clean the tray 10 compared with prior art gratings.

The trays moreover lend themselves to stacking one partially inside the other. This together with the feature of lightness of the trays means they can be transported in large numbers when empty, with a greatly reduced risk of factory worker injury and with a lower transport energy overhead. Furthermore the trays when stacked in an empty condition occupy relatively little storage space.

Uses of the tray 10 for the processing of food, and transport, stacking and storage as described are within the scope of the disclosure hereof.

Food products produced using the tray 10 or by methods as described herein are likely to be of superior quality to prior art products. The production processes involve significantly reduced waste, and the production of uniform slices almost regardless of the location along a fillet from which they are cut. In view of this food products as disclosed herein are novel and inventive over the prior art.

The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge. Preferences and options for a given aspect, feature or parameter of the invention should, unless the context indicates otherwise, be regarded as having been disclosed in combination with any and all preferences and options for all other aspects, features and parameters of the invention.