Preservation Methods for fish

1.Freezing

Normally most of the fish can be frozen for around six months. They should be frozen and vacuum-packed with well sealing to prevent freezer burn. Oily fish do not freeze as well as lean fish because enzyme activity breaks down the fat. 

You can also glaze fish by repeatedly spraying it with water and freezing it, until the entire fish is coated with several layers of ice.

2.Smoking

Cold-smoked fish are prepared in smoking chambers in which the temperature reaches 22 °C to 25 °C. Usually, you need to smoke a thick fish for a longer time (maybe one to six days). The type of wood used can affect the color and flavor of the fish. You can keep the cold-smoked fish for around fourteen days in the refrigerator or for around two to three weeks if vacuum-packed and chilled. 

Hot-smoked fish is another method to smoke a fish. They can be kept for around three to four days, or three to four weeks if vacuum-packed. First, you need to soak the fish in a salt solution for about an hour. Then, you can smoke it for around thirty minutes to three hours depending on the thickness and the type of the fish. You can smoke the fish at 70 °C to 90°C, then you will get the smoked fish with a beautiful color and excellent flavor. You will get the smoky flavor nearly the end of the smoking process. During smoking, you need to keep the vents in the chamber closed, and the fire is doused with damp wood chips to make a dense and smoldering smoke.

3.Drying

The most common dried fish you can find are cod, pollock, haddock, leng and lumb. The best-known products are stockfish, in which the fish is gutted and head-removed and then air dried.

4.Salting

You can use a certain amount of salt to remove water from fish ,and also denature the fish protein

5.Marinating or Picking

You can marinate raw fish with a salt and vinegar mixture, which denatures the protein of fish. After marinating, the fish are placed in highly spiced and hot liquid. Marinated fish are only partially preserved and must be kept refrigerated. They can only be preserved for a short amount of time.

6.Canning

Canned fish is fully preserved and can be kept at room temperature. High-pressure canning brings the temperature of the fish to above 100°C which also kills all the harmful microorganisms and spores. You can preserve the canned fish like sardines for about a year.

7.Surimi

This washed fish paste has been produced in Japan for many years. Flesh of fish is washed frequently and kneaded into a smooth white mass. Starch and seasonings are added before baked or cooked. The best-known product of surimi is crab stick (imitation crab meat).