Frozen mackerel

Atlantic and Spanish mackerel are sold to retailers as the fresh product, either as fillets or as the round uncut fish. Amounts of Spanish mackerel also go to local fresh fish market. Spanish mackerel also is also sold as marine mammal food to aquarium-type attractions.

Spanish Mackerel

Some are frozen by placing the round fish in pans and holding at -18° C, or below in rooms with or without circulating air.

The fish, frozen as a block, are sprayed with water for purposes of glazing to prevent dehydration and held in the frozen state until defrosted for sale to restaurants or retail outlets. Freezing, frozen storage and thawing affect the quality and shelf stability of fish and seafood. During frozen storage microbiological changes in fish and seafood are minimal.

Frozen mackerel mince blocks without glazing lost 35% of its initial weight when stored at -18 C for 80 days.
Frozen mackerel

Frozen tuna aboard the boat

Most tuna fish fishing boats make trips lasting for several months and for this reason, the fish are usually frozen aboard the boat.

The freezing process depends on the type of tuna. For bluefin tuna as an example, fisherman first cut the tail and gills, then gut bled and freeze it t -65 C for 35horus before placing them in to the fish hold at -60 C.

Normally in freezing, the whole fish are cooled in large well with refrigerated sweater circulated through it at 28 F (-2.2 C). Once the fish are cook led, the refrigerated seawater is pumped out of the well, and it is replaced with refrigerated bone at 10 F (-12.2 C) or lower.

When the fish are frozen, the brine is pump out of the well, and the fish are kept frozen in the dry well by circulating mechanically refrigerated air.

In one system brine is sprayed on refrigerated pipe coils located in the hold of the vessels until a coating of ice one foot thick or more is frozen. The compartment is then filled with fish and is flooded with brine. Accumulated ice provides refrigeration capacity needed to chill the brine and freeze the fish.

They remain there until the boat arrives at port.
Frozen tuna aboard the boat

World of Fisheries

World of Fisheries
With an increasing percentage of fish going to the frozen and fresh markets, and the increasing requirement for high quality waste (secondary raw materials for by products), the attitude for the entire fishing industry is changing.

Although many problems related to seafood are much more complicated than some for those faced by agriculture, the fishing industry has been grossly negligent in its concern about quality control of raw materials.

The new industry means technology from harvest through handling, processing, holding and distribution to the final market. This sequence must be started by the fisherman.

The number of experts differing on the role that food from the main and freshwater bodies of the world should play in mankind futures staggers the imagination.

The complex physical and biological environments, the difference in food requirements between many developed and developing nations, and the political relationships between nations (particularly those on continental and island sea coats) greatly complicate predications of these food resources and the ability to chart a course of action.

The highly nutritious protein foods form the sea and inland fresh waters do have an important place in feeding people. This impact can be increased tremendously through both harvesting and aquaculture operations.

Like all modern developments based on technology, the solution involves major financial investments, enlightened management and wise application of the technology.
World of Fisheries

Processing of Cod

Processing of Cod
At the processing pant, the cod are washed and filleted, skinless.

Fillets that are to be frozen for the retail trade are packed in 1 lb (454 kg) waxed carton with or without being first wrapped in moisture vapor-proof plastic.

The fillets may have been passed through a weak brine (10 – 45% saturated salt solution) prior to packaging. For purposes of freezing, retail sized cartons of fillets may be placed on trays, the trays placed on racks, and the racks wheeled on top a blast freezer where very cold air is blown over the product, or the cartons may be plate frozen by being placed in trays in contact with refrigerated plates at -28 degree F (- 33.3 degree C).

Some cod fillets are frozen, usually in a plate freezer, and then cut into fish sticks or fish portions that are then breaded in a batter of flour, dried milk solids, egg solids, spices, and flavoring.

The product is then packaged in retail-sized units and held frozen until sold to customers.

Salted cod was once a major export commodity of the United States, only very little cod is now salted in this country. To produce salted cod, the fish are beheaded and split longitudinally; the backbone and the abdominal cavity lining are remove, washed and layer salted in closed casks (brine salting), in open tubs, or simply in open piles on a low platform (dry salting).

Most of the salted cod is produced by dry salting that is done to produce either a lightly salted product or a heavily salted product. The lightly salted product requires many days to complete, has a relatively low salt content (less than 10%), has better organoleptic properties than the heavily salted once, but it is not shelf stable, the heavily salted product requires week to complete, has a high salt content (about 30%) and is shelf stable.
Processing of Cod

King Crab

King Crab
This species is not a true crab but is similar to crabs in structure and habits. It is much larger than other crabs, attaining a spread of about 5 ft (1.5m) and a weight of about 24lb (10.9kg).

King crabs are caught off central Alaska to the Aleutian Islands and off the islands of northern Japan. They are harvested with large rectangular pots. Aboard boats, the crabs are held in the live state in wells of circulating seawater.

King crab meat is either canned or frozen. In canning, the whole crab is cooked in boiling water, after which the meat is squeezed out between rubber rollers. The meat is then washed, packed in cans in a weak brine, and the cans are sealed, heat processed, cooled and stored. The meat may be frozen in large block for the restaurant trade. The legs and claws are also frozen for retail outlets and restaurant.

It properly packaged and frozen to a temperature of 0 degree F or below and held at this temperature. King crab meat has a high quality storage life of at least 12 months. Lower storage temperatures provide for an even longer storage life.
King Crab