GB2074840A - Methods of a storing/transporting fish to preserve freshness - Google Patents

Abstract

The method for extending the period of freshness of fish, particularly pelagic fish and especially so-called "blue fish", such as anchovies, sardines, herrings, pilchards, mackerels, etc., comprises placing the freshly caught fish in tanks or ponds on a fishing vessel which contain a liquid, e.g. sea water, that is maintained at a controlled temperature, preferably about 0 DEG C., so that the liquid will envelop each fish and avoid any squeezing pressure thereon. Similar tanks can achieve the same results in the storage and transportation of fish ashore.

Description

SPECIFICATION Methods of storing/transporting fish to preserve freshness This invention relates to methods of extending the period of freshness of fish, particular pelagic fish and especially those fish known as so-called "blue fish", e.g. anchovies, sardines, herrings, pilchards, mackerel, etc.

In the specific field of the storing and transportation of so-called "blue fish" to market immediately after being caught, the systems presently used can only maintain the fish in a "fresh" condition for two, or at most three, days.

Obviously, the fish could be stored in refrigerated chambers, but then the typical appearance of "freshness," which is the main attraction of this appreciated fish, is lost. Therefore, the only available handling systems are the presently-used systems which comprise packing or heaping the fish into baskets or the like after they have been caught, and subsequently packing them into cases for transportation purposes. Obviously, fish packed in this way are compressed and squeezed by their own weight and lose their blood. This is recognised to be the main cause of rapid deterioration.

By thoroughly considering the facts which cause this rapid deterioration, it has been concluded that the problem can be solved only by avoiding any heaping up and squeezing of freshly caught fish. This conclusion and thorough investigations have finally suggested the solution to the problem. The solution, though simple does achieve the desired result, that is, to obtain by natural means an extended period of freshness of the fish.

In accordance with the invention there is provided a method of extending the period of freshness of fish, particularly pelagic fish and especially so-called "blue fish", comprising placing the freshly caught fish in container means on a fishing vessel and containing a liquid which is maintained at a controlled temperature of approximately OOC and which surrounds the fish so as to floatingly submerge the same.

Preferably, the freshly caught fish is placed in tanks or ponds arranged on the vessel and containing sea water in such a proportion as to floatingly submerge the fish, the seat water being brought to and maintained at a temperature just below OOC, that is, just above its freezing point.

The invention also extends to the transportation of the fish by land, according to the same principle, suitable containers or tanks being provided into which the fish is introduced immediately and wherein the same conditions exist as in the tanks on the fishing-vessel. The method described above gives outstanding results and has proved to be capable of at least doubling the length of the period of the typical fresh condition of so-called "blue fish" and the like. This fishing produce can thus be transported to markets further afield than heretofore possible, with reduced risk of deterioration, and minimising or eliminating any loss of fish due to deterioration.

These and other details of the method of the invention will be apparent from the following description.

The basic principle of the method according to the invention comprises the pouring of a liquid, for example salt water such as sea water, into refrigerated tanks or containers and the introduction of the fish thereinto so that the fish will be surrounded by liquid which prevents any squeezing pressure being exerted on the fish (which is impossible if the fish is heaped up in a basket or the like), so that the factors which negativeiy affect the fish quality and give rise to deteriorat;on of the fish are avoided.

These tanks, which in the first instance are located on the fishing vessels and are sized to suit the size of such vessels, are provided with refrigerating means adapted to maintain the temperature of the liquid therein at slightly below 00 C (sea water freezes at about 20 to -3 OC).

The proportion of the liquid, e.g. sea water, in the tank to the quantity of fish to be submerged therein is approximately 20% so as to allow the fish to be floatingly submerged in the liquid, i.e.

surrounded by liquid which will thus form a liquid enveloped around each fish, rather like a protective sleeve. Due to the density of sea water (1016-1025 gr/dm3), a submerged fish is subjected to very little upward pressure and this will ensure a status of free fluid buoyancy, which is the basic principle of the invention. As stated above, the same basic principle applies in the transporation of fish by land, or indeed by air. For land transportation the tanks containing liquid and fish, and again maintained at said controlled temperature, are located on suitable motor vehicles which transport them to market areas, with the result that the period from the time that the fish is caught to the time of delivery to a customer can thereby be extended up to 5-6 days with no risk of adversely affecting the typical freshness of the fish.

Obviously, the tanks (for use at sea and/or ashore) can be of various sizes and can be made of any suitable material. They may or may not have a cover, and if desired they can have insulated walls, all depending upon the specific requirements.

They are designed, anyway, to carry out the basic principle of the invention, i.e. to create, by floatingly submerging the fish in a liquid such as sea water, a condition for preservation and transportation which prevents the fish from being squeezed, and which protects the fish against the factors which could quickly cause it to deteriorate, thus extending the period of freshness to at least double that heretofore accepted as being the maximum possible using conventional methods.

The containers may be such that they are specific to use on board a sea-going vessel, or specific to use on a land-based vehicle, with the fish being transferred from one to the other. Alternatively, the containers may be designed so that the containers themselves are interchangeable between vehicles and vessels, thereby minimising handling of the fish.

Finally, the invention can also be applied to the storage of fish in commercial containers for direct retail sale in shops and supermarkets, such containers affording substantially the same conditions for the fish as on the fishing vessel.

Claims (7)

CLAIMS:

1. A method of extending the period of freshness of fish, particularly pelagic fish and especially so-called "blue fish", comprising placing the freshly caught fish in container means on a fishing vessel and containing a liquid which is maintained at a controlled temperature of approximately OOC and which surrounds the fish so as to floatingly submerge the same.

2. A method as claimed in claim 1, in which the liquid is sea water.

3. A method as claimed in claim 1 or 2, in which said container means are tanks which are removable from the vessel.

4. A method as claimed in claim 1 or 2, which includes transferring the fish from said container means to further container means on a land-based vehicle for transportion, said further container means affording substantially the same liquidprotected conditions for the fish as the container means on the vessel.

5. A method as claimed in any preceding claim, which includes storing said fish under similar controlled conditions of submerged flotation in containers awaiting sales.

6. A method of extending the period of freshness of fish substantially as hereinbefore described.

7. Fish when preserved and/or transported and/or stored by a method as claimed in any preceding claim.