Different processing and preservation methods like salting, drying, smoking, chilling, freezing, chemical treatments, as well as combination of these two or more methods (referred to as hurdle technology) are used for the preservation of fish.
Salting is one of the oldest techniques for preserving fish, and it is a traditional processing method in many parts of the world. Salting is a simple method of fish preservation, with salt and fish, and sometimes water, as the only ingredients.
Salted fish products have been shown to be safe for consumption. The main purpose of salting is to separate water from the fish and replace it with salt. Thus, the water concentration in fish decreases.
As the water moves out, the salt moves in, penetrating deep into the flesh of the fish. Water is essential for bacteria (germs) to grow, so if the water is removed, bacteria cannot grow.
The salting process can be wet, dry or a combination of the two. Salting followed by open-air sun drying is commonly used by traditional processors because it is cheaper and easily adaptable. Only a few traditional processors use solar drying.
The principle is to keep the fish for a long time in brine. The equipment needed consists of a watertight container, which can be a tin, drum, canoe, barrel, etc. While in dry salting the fish is salted but the juices, slime and brine are allowed to flow away. Dry salting can be done in an old canoe, or on mats, leaves, boxes, etc. In any case, the brine formed by the fish juices and the salt must be allowed to run away.
Salting is a process where the common salt (NaCl), sodium chloride, is used as a preservative that penetrates the tissue; hence slows the bacterial growth and deactivates the enzymes. Salting helps the drying process too, as it binds the water, making it unavailable to bacteria.
Some of the factors involved in salting of fish which play important role are purity of salt, quantify of salt used, method of salting, and weather conditions, flavor of the product.
It is important to use clean, dry salt for preserving fish. Dirty salt should not be used and if the salt is wet, it must first be dried. There are some special bacteria that like to live in salt-- these are called the salt-loving bacteria or halophiles that can spoil fish, producing unpleasant smells.
The flesh of groundfish, such as cod, contains about 80% water. When salt is added to the surface of a fish, some dissolves in this water. If the fish is examined shortly after salting, it will be found that the surface has become quite sticky. This is because the salt affects the protein in the flesh and makes it swell and absorb salt and water.
Fish preservation by salting method
