IES20070024A2 - A process for preparing bivalve shellfish - Google Patents

Abstract

This invention relates to a process for preparing bivalve shellfish and in particular to a process for preparing mussels. The process comprises initial cleaning and preparation steps for the bivalves before carefully placing the bivalves into large perforated rigid containers, vibrating the containers to compact the bivalves therein and sealing the bivalves in a closed configuration in the containers. Once sealed in the containers, the containers are placed in cooking pots and the mussels are at least partially cooked in the cooking pots before the cooking pots are filled with cold water to cool the bivalves. Once cooled, the containers are removed from the cooking pots and taken to a blast freezer where the bivalves are frozen in situ in the containers. Finally, the frozen bivalves are removed from the containers and inspected before being packaged for distribution. <Figure 1>

Description

This invention relates to a process for preparing bivalve shellfish.

Typically, bivalve shellfish such as mussels, clams, scallops and oysters are sold fresh loosely in fishmongers, supermarkets and other outlets with dedicated counters for the sale of fresh shellfish. There are, however, numerous problems with selling shellfish in this manner. First of all, it is necessary to provide a dedicated shellfish counter so that the shellfish may be stored separately from other food items for health and safety reasons. Another problem with selling shellfish in this manner arises due to the fact that typically shellfish does not have a very long shelf-life resulting in significant amounts of wastage of unsold shellfish for the retailer. Finally, a third problem with selling shellfish in a fresh state is that the retailer is at the mercy of the suppliers who provide the shellfish, normally, the suppliers cannot guarantee supply all year round due to the fact that many shellfish products are predominantly 0 seasonal crops that may be unavailable for significant periods throughout the year.

In order to overcome the inherent difficulties with the sale of fresh shellfish, retailers have begun to stock precooked frozen shellfish in their stores. Various methods have been proposed for cooking the shellfish. One such method commonly used with bivalves and mussels in particular is that disclosed in the applicants own granted UK Patent No. GB2342274. This method entails pre-cooking the mussels in individual bags and thereafter freezing the bags so that the mussels may be provided in a frozen packaged form. This allows for the provision of shellfish the full year round, obviates the majority of wastage on behalf of the retailer due to the significantly longer shelf-life of frozen shellfish, and furthermore avoids the necessity for the retailer to provide dedicated counters in their premises for fresh shellfish as the frozen packaged shellfish may be placed in close proximity with other goods without fear of cross-contamination.

IE 07 0 Ο 24 Typically, the known processes of preparing bivalves and mussels in particular entail numerous preparatory steps of washing, purification and de-byssing of the mussels as well as re-growing a small byssus in the bivalves before vacuum packing the bivalves in either a single or a multiple-layer in a relatively rugged, flexible bag. The bag containing the mussels is then sealed and the bivalves in the bag are cooked for a predetermined period of time. Once the bivalves have been cooked for the predetermined period of time, they are allowed to cool before being frozen and thereafter transported to the retail outlets for onward sale to customers. Although this method has proven to be quite useful and cost efficient on behalf of the supplier and the retailer, as well as being of benefit to the consumer who is able to purchase bivalves the full year round, there are various difficulties with the proposed processes for preparing the bivalves themselves.

One problem with the known processes of preparing bivalves is that the bivalves must be vacuum packed into packages prior to the cooking and freezing process. This has several disadvantages. First of all, the bivalves must be sold in packages of predetermined size and cannot be sold individually. Additionally, the bivalves cannot be sold in a very wide range of packages as this becomes economically unfeasible for the supplier of the frozen bivalves to produce. Therefore, the choices of the consumer are limited in some way. Secondly, as the bivalves are in a non-frozen state when being vacuum packaged, there is a greater chance of the bivalve shells being broken during packaging, leading to increased waste.

Furthermore, according to the known processes, the bivalves must be cooked in the packaging itself. This has numerous disadvantages. First of all, by cooking the bivalves in the packaging, the packaging acts as a thermal insulator and therefore the cooking process takes longer to carry out which increases the costs to the manufacturer. Furthermore, as the bivalves are cooked in the packaging and subsequently frozen in the same packaging, the packaging is subjected to relatively extreme high and low temperatures and therefore special plastics materials must be used that is capable of withstanding both freezing cold temperatures and boiling water temperatures as well as being suitable for vacuum packaging. These packaging materials are usually relatively expensive. Furthermore, as the packaging is subjected to these various different preparation stages and differences in IE 07 0 0 24 temperature, it is not uncommon for a number of bags to perish during the process resulting in significant waste on the part of the supplier.

In addition to the above, it is not uncommon for at least some of the bivalves to be in a partially open state subsequent to vacuum packaging and therefore, using the specific example of mussels, some of the mussels in the bag would be cooked in an open state and this will result in some of the mussels in the bag cooking at different rates to the others, resulting in a lack of uniformity of the cooked mussels texture and quality. This can have a detrimental effect on the delicate meat of the mussels. Furthermore, there is a tendency of the mussels to lose their natural juices which are spread over the interior of the bag. Once frozen, this sticks all of the mussels together thereby preventing them from being used individually.

Another problem with the known methods and as mentioned above is that the number of sizes of bags that are used is quite limited. In order to attempt to achieve uniform cooking of the bivalves in the packaging, it is necessary to ensure that the bivalves are not too far from the surface of the packaging. Therefore, it is impractical to provide these bivalves in very large sized bags e.g. 5kg or 10kg bags that may be useful in industrial cooking processes. All of the products currently sold are typically provided in 1 kg and in some instances 2kg bags and to provide the bivalves in larger bags would be deemed impractical as the bags themselves would be rather unwieldy due to the fact that the bivalves must be relatively near the surface of the bag to ensure even cooking, thereby requiring a bag with a very large surface area for larger amounts of bivalves. Therefore, even in industrial cooking applications, it has been the norm to provide the bivalves in smaller amounts and this wastes a significant amount of time as the operators in the industrial cooking process production line must spend a considerable amount of their time opening smaller bags with relatively few bivalves contained therein whereas it would be far more convenient for them to be able to use a much larger bag of bivalves and not waste time continuously opening bags of bivalves.

It is an object therefore of the present invention to provide a process for preparing bivalve shellfish that overcomes at least some of these difficulties which occur with the known processes, that is simple and cost effective to perform.

IE 070 Ο 24 Statements of Invention According to the invention there is provided a process for preparing bivalve shellfish comprising the steps of: inspecting the bivalve shellfish and removing any unsuitable bivalves; cleaning the exterior of the bivalve shellfish; grading the bivalve shellfish and removing any substandard shellfish; placing the shellfish in a retention tank containing ultraviolet treated oxygenated salt water which has a salinity that exceeds the normal threshold for bivalves, forcing the bivalves to filter feed thereby removing particulate contaminants and retaining water; carrying out a further inspection of the bivalve shellfish and removing any unsuitable bivalves; placing the shellfish in a second retention tank containing ultraviolet treated oxygenated salt water which has a salinity that exceeds the normal threshold for bivalves, forcing the bivalves to filter feed thereby removing particulate contaminants and retaining water; introducing the bivalves from the second retention tank to a suitable rigid container through a charging aperture in the container; vibrating the container with the bivalves therein for a predetermined period of time until the bivalves settle into a compacted configuration in the container; placing a suitable lid on top of the compacted bivalves in the container and securing the lid in place so that the lid exerts sufficient force on the bivalves in the container to maintain the bivalves in a compacted, substantially IE 0 7 0 0 24 closed configuration; placing the container with bivalves therein into a cooking pot and at least partially cooking the bivalves in the cooking pot; after the bivalves have been at least partially cooked, cooling the bivalves in the container by delivering cold water into the cooking pot housing the container; and once the bivalves have been cooled, removing the container with the bivalves therein from the cooking pot and thereafter freezing the bivalves in situ in the container.

By having such a process, it is possible to arrange all of the bivalves in a tight compact configuration in the container with the bivalves closed. The lid will contain the bivalves in a compacted closed configuration thereby preventing the bivalves from opening. Bivalves, and mussels in particular, have a tendency to open due to degradation of the abductor muscle during cooking. However, the constant force provided by the lid and surrounding bivalves will keep each of the bivalves in the container in a shut configuration, thereby allowing the bivalves to cook in a uniform manner retaining their natural juices. In addition to this, it has been found that the bivalves are able to cook more uniformly when outside a packet and therefore this allows for much tighter quality control and uniformity of product to be achieved by the supplier. Furthermore, the bivalves can be placed in a cooking pot which is used to first of all at least partially cook the bivalves and thereafter the cooking pot may be filled with cold water to cool the bivalves down prior to freezing the bivalves. This significantly reduces the amount of time taken to prepare the bivalves and increases the efficiency of the process. Furthermore, the process provides a bivalve shellfish product that will allow the bivalves to be handled individually in a frozen state after distribution.

In one embodiment of the invention there is provided a process in which the process comprises the further steps of: ΙΕ ΰ 7 0 Ο 24 removing the frozen bivalves from the container; discarding any unsuitable bivalves; and packing the frozen bivalves for shipping.

Once the bivalves have been frozen, they may be removed from the container individually and placed in suitable packaging where they will remain in a closed frozen state until thawed. By using the process according to the invention, it is possible to cook the bivalves and freeze them prior to packing the bivalves. By doing this, the bivalves may be packed into a variety of different sized bags and indeed the bivalves may be packaged into a much larger bag than was previously the case, for example a 5kg or a 10kg sized bag that is practical particularly in industrial cooking situations. Any bivalves that have been damaged inadvertently during the process may be removed and only fit bivalves are packaged. This reduces the amount of wastage on the part of the manufacturer and furthermore the chance of the bivalves shattering on packaging is significantly reduced as the bivalves are now in a frozen state. Furthermore, by packing the bivalves after freezing, the materials used for the packaging do not have to be able to withstand the thermal shock of going from boiling water to relatively very cold water in a short space of time and therefore there will be less spoiled bags and less expensive packaging materials may be used, all of which are of considerable benefit to the producer.

In another embodiment of the invention there is provided a process in which the process further comprises the intermediate step of glazing the bivalves subsequent to freezing and prior to packaging. This will allow for the bivalves to have an attractive outward appearance. Preferably, the glaze will comprise one of sea water, salted water/brine, potable water or juices from the cooking process and will improve the organoleptic properties of the finished product.

In one embodiment of the invention there is provided a process in which the bivalves are mussels and the intermediate steps subsequent to grading and prior to introducing the bivalves into a container are carried out of: IE Ο 7 Ο ο 24 debyssing the remaining mussels; and retaining the debyssed mussels in the retention tank until such time that a small byssus re-grows replacing the removed byssus to seal the bivalves and allowing the mussels to retain the water therein.

In one embodiment of the invention there is provided a process in which the bivalves are cooked in hot water at a temperature between 75°C and 99°C. Preferably, the bivalves are cooked in hot water at a temperature between 80°C and 90°C.

In a further embodiment of the invention there is provided a process in which the bivalves are cooked for between 2 and 10 minutes. Preferably, the bivalves are cooked for between 3 and 5 minutes.

In another embodiment of the invention there is provided a process in which the cold water delivered into the cooking pot housing the container is at a temperature of between 1 °C and 20°C. Preferably, the cold water is at a temperature of the order of 10°C.

In one embodiment of the invention there is provided a process in which the container is vibrated for between 10 and 90 seconds. Preferably, the container is vibrated for between 20 and 30 seconds.

In a further embodiment of the invention there is provided a process in which the container is such to allow equal heat penetration to the bivalves in the container during cooking and in which the bivalves are cooked uniformly at the same pace in the container, the container comprising a body having a base, a side wall and a charging aperture, the side wall having a plurality of apertures formed therein, the container further comprising an internal pipe formed along its length, the internal pipe extending substantially the entire length of the body and being arranged substantially co-axially with the central axis of the body, the container further comprising a lid, releasably securable to the container across the charging aperture.

This is seen as particularly useful as such a container will allow for the bivalves to be IE Ο7ο cooked uniformly in the container allowing the supplier to provide a consistent quality product. By having the internal pipe extending substantially the entire length of the body and arranged substantially co-axially with the central axis of the body, the temperature will be evenly distributed throughout the container. Hot water is allowed to circulate around the sides and also into the centre of the container thereby allowing the core temperature of the meat to reach at least 74°C for 2 minutes. Hot water is delivered to the container by way of a pipe to the internal pipe of the container. This will inactivate even the most heat resistant pathogens. The void in the centre of the container of bivalves prevents the bivalves from becoming too dense for the effective penetration of heat to the core. Hot water is delivered to the container by way of a pipe to the base of the cooking pot.

In one embodiment of the invention there is provided a process in which the container body is substantially cylindrical in shape. This will allow for very uniform positioning of the bivalves and uniform cooking of the bivalves in the container.

In another embodiment of the invention there is provided a process in which the internal pipe is cylindrical in shape and has a diameter of the order of between 15% and 25% of the diameter of the container. Preferably, the internal pipe is cylindrical in shape and has a diameter of the order of 18% of the diameter of the container. Ideally, the internal pipe is concentric with the body of the container. This will ensure that the mass of bivalves in the container does not become too dense to allow proper heat penetration to all the bivalves.

In another embodiment of the invention there is provided a process in which the apertures are evenly circumferentially spaced about the side wall of the container. By having the apertures spaced evenly about the side wall, the water will be allowed access the bivalves contained in the container in a uniform manner.

In a further embodiment of the invention there is provided a process in which both the base and the lid of the container are each provided with a plurality of apertures. In this way, water will be allowed access the bivalves in the container through the lid and the base, this will allow for more uniform cooking of the bivalves contained therein.

In one embodiment of the invention there is provided a process in which the salinity of the ultraviolet treated oxygenated salt water in the retention tank is of the order of between 32 and 34 parts per thousand. Preferably, the salinity will be of the order of 33 parts per thousand. This is seen as particularly preferred as it will enable mussels in particular to start to feed and begin to grow a new byssus.

In another embodiment of the invention there is provided a process for preparing bivalves in which the process further comprises the intermediate step of draining the hot water from the cooking pot prior to delivering the cold water into the cooking pot. By draining the hot water from the cooking pot prior to delivering the cold water to the cooking pot, the bivalves will cool in as short a time as possible so that they may be frozen as soon as possible after cooking.

Detailed Description of the Invention The invention will now be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying drawings in which: Figure 1 is a side view of a production line for carrying out the process according to the invention; and Figure 2 is a front perspective view of a container used in the process according to the invention; Referring to the drawings and initially to Figure 1 thereof, there is shown a production line, indicated generally by the reference numeral 1, for carrying out the process for preparing bivalve shellfish according to the invention. The production line 1 comprises a hopper 3, a conveyor belt 5 led from the hopper 3 to a brush cleaner 7, otherwise referred to as a de-dumper, and a chute 9 led from the brush cleaner 7 to a grading station 11. The grading station 11 comprises an inclined screen (not shown) having a plurality of apertures therein for through-passage of unsuitable shellfish below a - 10 predetermined given size from the process. A conveyor 13 is led from the grading station 11 to a debyssing station 15 which in turn feeds a conveyor 17. The conveyor 17 carries debyssed bivalves from the debyssing station 15 to a retention tank 19 having ultraviolet treated oxygenated salt water therein which has a salinity that exceeds the normal threshold for bivalves.

An inspection conveyor 21 is led from the retention tank 19 to a water-filled second retention tank 23 where the bivalves are stored until needed and a further conveyor 25 is provided to remove the bivalves from the water-filled storage tank 23 and deposit bivalves in a container 27 located on a weighing station 29. A twin crane 31 is mounted on and moveable along a rail 33. The twin crane is provided with a pair of hooks 35, 37 for engagement of a pair of containers 29. A pair of vibrating platforms 39 are provided, each of which is suitable for reception of a container 27 thereon. The production line 1 further comprises three cooking pots 41, each of which is arranged to receive a pair of containers 27 therein. There is further provided a hot water buffer tank 43 and a cold water buffer tank 45 along with piping 47, 49 led from the hot water buffer tank and the cold water buffer tank respectively to each of the three cooking pots 41. Each of the hot water buffer tank 43 and the cold water buffer tank 45 are provided with a pumping unit 51, 53 respectively to pump water from the tank to one or more of the cooking pots 41.

In use, mussels or other bivalve shellfish are delivered into the hopper 3 from which they are fed on to the inspection conveyor 5. The bivalves are checked for suitability on the conveyor 5 and any unsuitable bivalves are removed. The inspection conveyor 5 carries the bivalves to the brush cleaner 7 in which any detritus or other materials are removed from the exterior of the bivalves thereby providing a relatively clean shelled product. Once cleaned, the bivalves are then gravity fed along chute 9 to a grading station 11 where any substandard, undersized bivalves are removed from the remaining process by dropping through a grading screen (not shown) in the grading station 11 for subsequent removal. The remaining satisfactorily sized bivalves pass over the grading screen and are picked up by the conveyor 13 which transfers the bivalves to the debyssing station 15. The debyssing station 15 removes the byssus, which during its life is the part of the bivalve used to cling to another object for stability, from each of the bivalves. - 11 Once debyssed, the bivalves are transferred to the conveyor 17 and passed to a retention tank 19 containing ultraviolet treated oxygenated salt water which has a salinity that exceeds the normal threshold for bivalves, in this case having a salinity level of 33 parts per thousand, forcing the bivalves to filter feed thereby removing particulate contaminants and retaining water. In the case of mussels, the mussels are kept in the retention tank until such time that a small byssus re-grows replacing the removed byssus to seal the bivalves and allowing the mussels to retain the water therein. Typically, the bivalves are kept in the retention tank for of the order of 20 minutes.

After the mussels have begun to grow the small byssus and retain water, they will sink to the bottom of the retention tank and thereafter they may be drawn from the retention tank along inspection conveyor 21 and deposited in the water filled second retention tank 23. The bivalves are typically left in the retention for 20 minutes. As the bivalves progress along the inspection conveyor 21 they are inspected once again and any further unsuitable bivalves are removed. Although in the conveyor 21 is shown as a short section of conveyor, it will normally in fact comprise three separate sections and be suitable to allow inspection of the bivalves on the conveyor. However, for convenience, the inspection conveyor 21 has been shown as a relatively short section. When needed, the bivalves are removed from the water-filled storage tank 23 by the conveyor 25 and loaded into a container 27 through a charging aperture 28 in the container. The container 27 is on a weighing station 29 and when a predetermined amount of bivalves have been loaded into the container 27, the conveyor 25 ceases to load the container and the container is moved from the weighing station 29 onto a vibrating platform 39. The container is moved from the weighing station 29 to the vibrating platform 39 using the twin crane 31 which is mounted on and moveable along the rail 33, in this case a rolled steel joist. One of the hooks 35, 37 of the twin crane is used to engage a loop (not shown) on the container 27. The container is vibrated for between 20 and 30 seconds to compact the bivalves in the container. Once the bivalves have settled into a compacted configuration, a lid (not shown) with perforations therein is placed on top of the bivalves in the container and secured in place so that the lid exerts a force on the bivalves in the container, maintaining the bivalves in a compacted, closed configuration. The crane 31 is then used to lift the container and the crane is - 12 moved along the rail until the container is above one of the cooking pots 41. The container 27 is then gradually lowered into the cooking pot 41.

Once the container 27 is inside the cooking pot 41, the cooking pot 41 is filled with hot water at a temperature of between 80°C and 90°C, and the bivalves are cooked for between 3 and 5 minutes so that the core temperature of the meat is allowed to reach at least 74°C for 2 minutes. The hot water is delivered into the cooking pot 41 from the hot water buffer tank 43 along piping 47 using the pumping unit 51. Once the mussels are at least partially cooked for the desired time, the hot water is drained from the cooking pot 41 and allowed to flow back into the hot water buffer tank 43 and the cooking pot 41 is filled with cold water at a temperature of approximately 10°C. The cold water is supplied to the cooking pot 41 from the cold water buffer tank 45 along piping 49 using pumping unit 53. Once cooled sufficiently, the container 27 is removed from the cooking pot 41 and stacked on a pallet 55 on the floor 56 from where it is taken to a blast freezer (not shown) for freezing of the bivalves in the container. The blast freezer is suitable for receiving a number of containers 27 therein and freezing the bivalves in the containers quickly. Once frozen, the bivalves may be taken from the blast freezer to an inspection area (not shown) where any damaged bivalves may be removed from the process and discarded. There may be provided a glazing machine (not shown) for glazing the frozen bivalves with sea water, potable water, salted water/brine or the cooking juices from the previous cooking stages once they have been removed from the container. The remaining suitable bivalves are then packaged and are ready for shipping.

It will be understood that the above process has been described in detail in relation to the preparation of mussels in particular. Accordingly, a description is given of removal of the byssus and also of retaining the mussels in a retention tank until such time that the mussels re-grow a small replacement byssus. This however may not be necessary with other types of bivalve shellfish such as for example clams (all species), cockles, oysters and the like. However, it will further be understood that the process described above could be easily modified to take into account the fact that debyssing and significant time in the retention tank is unnecessary and may be different for other bivalve shellfish in which case the steps may be either skipped altogether as appropriate or reduced in time if necessary depending on the bivalve shellfish being used.

Referring now to Figures 2 of the drawings, there is shown a container suitable for use in the process for preparing bivalves, indicated generally by the reference numeral 27. The container 27 comprises a body 61 having base 63, a side wall 65 and a charging aperture 28. The side wall 65 has a plurality of apertures 69 formed therein, evenly spaced about its surface. In fact, the side wall 65 is perforated with a plurality of apertures substantially about the majority of its surface. The container 27 further comprises an internal pipe 71. The internal pipe 71 is located internal the body 61 and extends substantially the entire length of the body 61 and is arranged substantially co-axially with the central axis of the body. The container 61 further comprises a lid 73 releasably securable to the container across the charging aperture 67. Both the internal pipe and the body are substantially cylindrical in shape, the base and the lid also have a plurality of apertures formed therein for even distribution of water there-through. The internal pipe 71 is arranged concentrically with the body 61.

In use, the bivalves are delivered into the body of the container 27 between the side wall 65 of the body and the exterior of the internal pipe 71. A predetermined amount of bivalves are fed from the water-filled tank 23 via the conveyor 25 into the container 27. Typically, 100 kilograms of bivalves may be inserted into the container. Once the predetermined amount of bivalves has been delivered into the container, the container is lifted from the weighing station 29, which may additionally include a water tank, and placed onto a vibrating table 39. The vibrating table is then allowed to vibrate until all of the bivalves have assumed a compacted configuration. This typically will take between 10 and 90 seconds, preferably between 20 and 30 seconds. Then, subsequent to vibration when the bivalves are in a compacted configuration, a lid 73 is placed tightly on top of the bivalves in the container and secured in place, thereby holding the bivalves down in a closed, compacted configuration.

The container 27 is then placed into a cooking pot 41 wherein the bivalves are cooked using hot water. Alternatively, steam may be used to cook the bivalves. Once the cooking time has elapsed, the cooking pot 41 is drained of the hot water if IE 07 0 0 24 - 14 appropriate, and filled with cold water to cool the bivalves in the container. Once the bivalves have cooled to an appropriate temperature, the container is picked up and moved along the rail 33 onto the pallet from where it will be delivered to a blast freezer. Once the bivalves have been frozen, the bivalves and container are then taken out of the blast freezer and brought to a final preparation area (not shown) where the bivalves are removed from the containers, placed in a glazing machine where they are sprayed with a glaze of potable water or sea water (salt water) and are thereafter vacuum packaged if desired. It is not essential to vacuum package the bivalves though.

Preferably, the hot water is at a temperature of between 75° and 99°C. It is envisaged that the hot water will in fact be between 80°C and 90°C. Once the bivalves are cooked, which usually takes between 2 and 10 minutes, preferably between 3 and 5 minutes, the hot water is drawn out of the cooking pot and cold water is delivered into the cooking pot. Preferably, the cold water is between 1 and 20°C and ideally is at approximately 10 °C. This ensures that the bivalves will be cooled quickly and efficiently. It is further envisaged that prior to cooking the bivalves, they may be vibrated in the container for between 10 and 90 seconds. Preferably though, the container and bivalves will be vibrated for approximately 20 to 30 seconds. It will be understood that the cool water is discharged from the container, once the bivalves have been suitably cooled, into a buffer tank. Furthermore, the cooking line may run automatic cleaning procedures when the cooking process is stopped and there are no bivalves contained in the cooking pots. Each of the materials used in the cooking process may be made out of stainless steel including pipework, tanks, flanges and valves. Furthermore, the materials in the processing machines which are the cooking cylinders, hopper, conveyors and platform may also be made of stainless steel. The monorail crane may also be made of mild steel, although its moving parts may be made of stainless steel. Furthermore, the heat exchangers, buffer tanks, filters and pumps may be situated in either a boiler room or under the cooking pots 41.

In the embodiments shown, the brush cleaner 7 and the grader 11 are shown as two separate devices in the drawings for clarity however in practice the two actions could be performed in a single machine. Furthermore, although a pair of vibrating platforms Ιίθ7θθ24 have been shown in the embodiments described, a single vibrating platform could suffice and in practice will probably be used. The weighing station 29 has means (not shown) to monitor the amount of bivalves being loaded into the container and has means (not shown) to halt the conveyor 25 and hence the supply of bivalves when the predetermined amount has been filled into the container. Finally, in the embodiments shown, there are a number of crane units 31 shown on the rail 33 however it will be understood that in practice, a single crane unit will be used that moves along the rail 33 and that multiple units have been shown to indicate the various different functions of the crane unit 31. The crane unit 31 is able to move along the rail 33 in the direction of the arrow “A” and furthermore is able to lift and lower goods in the direction of the arrow “B” as shown in Figure 1(c).

In the specification, the terms “comprise, comprises, comprised and comprising” and the terms “include, includes, included and including” are deemed totally interchangeable and should be afforded the widest possible interpretation.

The invention is in no way limited to the embodiments hereinbefore described but may be varied in both construction and detail within the scope of the claims.

Claims (4)

1. ) A process for preparing bivalve shellfish comprising the steps of: inspecting the bivalve shellfish and removing any unsuitable bivalves; cleaning the exterior of the bivalve shellfish; grading the bivalve shellfish and removing any substandard shellfish; placing the shellfish in a retention tank containing ultraviolet treated oxygenated salt water which has a salinity of the order of between 32 and 34 parts per thousand, forcing the bivalves to filter feed thereby removing particulate contaminants and retaining water; carrying out a further inspection of the bivalve shellfish and removing any unsuitable bivalves; placing the shellfish in a second retention tank containing ultraviolet treated oxygenated salt water which has a salinity of the order of between 32 and 34 parts per thousand, forcing the bivalves to filter feed thereby removing particulate contaminants and retaining water; introducing the bivalves from the second retention tank to a suitable rigid container through a charging aperture in the container; vibrating the container with the bivalves therein for a predetermined period of time until the bivalves settle into a compacted configuration in the container; placing a suitable lid on top of the compacted bivalves in the container and securing the lid in place so that the lid exerts sufficient force on the bivalves in the container to maintain the bivalves in a υ 7 0 0

2. 4 - 17 compacted, substantially closed configuration; placing the container with bivalves therein into a cooking pot and at least partially cooking the bivalves in the cooking pot; after the bivalves have been at least partially cooked, cooling the bivalves in the container by delivering cold water into the cooking pot housing the container; and once the bivalves have been cooled, removing the container with the bivalves therein from the cooking pot and thereafter freezing the bivalves in situ in the container. A process as claimed in claim 1 in which the process comprises the further steps of: removing the frozen bivalves from the container; discarding any unsuitable bivalves; and packing the frozen bivalves for shipping. A process as claimed in any preceding claim in which the bivalves are mussels and the intermediate steps subsequent to grading and prior to introducing the bivalves into a container are carried out of: debyssing the remaining mussels; and retaining the debyssed mussels in the retention tank until such time that a small byssus re-grows replacing the removed byssus to seal the bivalves and allowing the mussels to retain the water therein. A process as claimed in any preceding claim in which the bivalves are cooked in hot water at a temperature between 80°C and 90°C, for between 0024

3. And 5 minutes and in which the cold water delivered into the cooking pot housing the container is at a temperature of the order of 10°C, the container is such to allow equal heat penetration to the bivalves in the container during cooking and in which the bivalves are cooked uniformly at the same pace in the container, the container comprising a body having a base, a side wall and a charging aperture, the side wall having a plurality of apertures formed therein, the container further comprising an internal pipe formed along its length, the internal pipe extending substantially the entire length of the body and being arranged substantially co-axially with the central axis of the body, the container further comprising a lid, releasably securable to the container across the charging aperture.

4. 5) A process substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.