Methods of Preserving Fish and Shellfish

Fish There are several methods in preserving fish. Fish preservation involves Chilling and Freezing, Salting, Fermentation, Drying and Dehydration, Smoking, Pickling and Spicing, and Canning. There is one thing first to consider, make sure that the fish that is going to be preserve is new and still fresh. The method of Chilling and Freezing; if the fish is exposed to a low temperature environment, the growth of the microorganisms could be prevented; this could lead to spoilage prevention. The appropriate temperature is 0 degree Celsius which involves the use of ice or a refrigerator. The use of ice for chilling is very much convenient and widely used in the markets. If you are going to use ice for fish preservation, make sure that you have sufficient amount of ice. To keep the fish properly chilled with ice, usually the coarser ice should be put on the top while the melted ice should be put below. Fish can also be preserved by the way of salting. Salt elements will lower the water content below the point where bacteria or microorganisms can no longer live and grow. In the time that water passes out from the tissues of the fish, the salt will going to penetrate the fish tissues until the salt solutions filled it in. This is called as the “osmosis” absorption process. Fish fermentation can also preserved fish. It is the process of breaking down the protein in the fish caused by an enzymatic action. It is called as hydrolization. In this process of fermentation, the flesh of the fish is allowed to get “ripe”; this is the state where the flesh of the fish will start to disintegrate before it is going to undergo “aging”. In normal process, fermentation takes up to 8 months. It will take less than a month that if pure salt is used and the temperature is increased from 37 degree Celsius up to 45 degree Celsius. In the later fermentation process, the activity is faster Drying and Dehydration is another technique. This involves the removal of water content from fish tissues until the moisture of the fish is extracted. In this process the growth of microorganisms is prevented. This can be done naturally using the heat of the sun. It is called as solar drying. Dehydration is another method in drying fish. It is done through the use of artificially heated air through the use of mechanical driers. Smoking is also another method in fish preservation. This process gives the fish a desirable flavor and odor as well as preserving it. Smoking is usually done through four processes. First is cleaning the fish. Second is brining which is soaking the fish in a brine solution. The third is drying and the fourth one is smoking the fish. In smoking process, the length of smoking time usually takes up to 30 to 45 minutes and the temperature is 85 degree Celsius. Hardwoods together with plant leaves are commonly used. Pickling and spicing; this method in fish preservation used vinegar and other spices. The growth of bacteria and other organisms is prevented by the acetic acid of the vinegar; the vinegar will preserve the fish as well as improves its taste. Canning is another method in fish preservation. It is the process of preservation that uses hermetically sealed containers such as bottles or cans. The procedure of heating the fish before and after canning can kill bacteria and other microorganisms that can cause fish spoilage.

Shellfish Live (without shells removed) shellfish should never be stored in air-tight containers or bags since the animals can die from lack of oxygen. They can be loosely covered with clean, damp paper towels or cloths to prevent them from drying out in the refrigerator. Store live shellfish above raw meat, or poultry, so juices don't drip on them. Do not store live shellfish directly on ice, since the melting fresh water may kill them. Optimum storage temperature is below 40°F, but temperatures of 35°F or lower (especially freezing temperatures less than 32°F) can kill shellfish. Use an accurate refrigerator thermometer to check and adjust the temperature of your refrigerator. Refrigerate them as soon as possible, within 90 minutes during hot weather, and follow the guidelines mentioned above. Be sure to only harvest shellfish from approved waters. Generally, it's best to eat them within one or two days (assuming they are kept refrigerated), but definitely before they die. Check for signs of life before preparing for consumption, and discard any dead shellfish (those with shells that do not close after lightly tapping them). Dead shellfish may contain high numbers of bacteria that could make you ill; don't eat them raw or cooked. Temperatures below 35°F will minimize bacterial growth and help shucked shellfish stay fresh longer, usually 4 to 7 days or by the "use by" date printed on containers. Refrigerator temperatures greater than 40°F will decrease shelf life. Frozen shellfish should be stored at 0°F or lower. Once shells are removed, shellfish can be placed in shallow, water-proof containers and stored in home freezers. Freezer temperature should be kept below 0°F. Since freezing does not improve seafood quality, only fresh, high-quality shellfish should be frozen. Do not freeze old shucked shellfish that should be discarded. Never shuck and freeze dead shellfish. Frozen shellfish should be thawed in the refrigerator, not at room temperatures. Canned shellfish that does not require refrigeration may be stored for a year or longer, as long as the can is not dented or rusty. Cans (of any food) that are swollen or bloated may contain life-threatening bacteria and should be discarded.