Fish spoils naturally; this is the reason why we need to know some of the methods and techniques that are use in preserving them. Food preservation particularly in fishes had been practiced since the ancient time. Ancient people had used different kinds of techniques in order to preserve fish.
Before thinking to preserve, one needs to consider the freshness of the fish as well as the other ingredients. This is an important factor as this affects the quality of the foods to be preserved.
The methods that are commonly used in fish preservation are Drying and Dehydration, Salting, Chilling and Freezing, Fermentation,Smoking, Pickling and Spicing and Canning.
The method of Drying involves the water removal of the water content of the fish from its tissue until such time that the fish moisture is extracted .With this method, the possible growth of the microorganism that causes food spoilage is prevented. It can be done using the heat of the sun and it is called as solar drying. In the Dehydration, an artificially heated air is use in dehydrating fish. This heated air comes from the mechanical driers.
The method of Salting is also use in order to preserve the fish. Through the use of salt the water content in the fish will become lower to the point that the bacteria or the organisms that causes spoilage can no longer grow or live. With salting, the water passes out from the tissues of the fish and the salt penetrates and filled the tissues in. This process of absorption is called “osmosis”
Chilling or Freezing is another kind of fish preservation wherein the fish is exposed to an environment with a low temperature. The microorganism cannot grow and live in this kind of temperature and as a result, the spoilage is prevented. It may involve with the use of ice or refrigerator with the appropriate temperature of0 degree Celsius.
The method of Fermentation is also used in preserving fish. This is a process in which the proteins in the fish are break through an enzymatic reaction. In this method the flesh of the fish to be preserved is allowed to get “ripe”. With this the flesh will start to disintegrate until such time that the flesh will undergo “aging”. Fermentation could take up to eight months in the normal process. However, this will only take for less than a month if pure salt is used and the temperature in the process will increased from 37 degree to about 45 degree Celsius.
The method of Smoking is another kind of method use in fish preservation. The effect of smoking does not only preserve the food but also gives the fish with a desirable odor and flavor. This involves the process of cleaning, brining and soaking, drying and smoking. In the smoking process, the fish is exposed to smoke for about 3o to 45 minutes with the temperature of about 85 degree Celsius. Hardwoods and or plant leaves are commonly use in smoking fish
The method of Pickling and Spicing involves using vinegar as well as other spices and ingredients as preservatives. The acetic acid of the vinegar prevents the bacteria and other microorganisms from growing which results for the preservation of the fish; this method also improves the fish’s taste.
The method of Canning involves the use of hermitically sealed containers. Before the canning process, the fish first undergoes heating procedure in order to kill bacteria and other organisms. As the fish is canned and sealed, the accumulation of some bacteria and other microorganism from the outside environment is prevented.