Fish preservation

[1][2] Ancient methods of preserving fish included drying, salting, pickling and smoking.

Sardines, pilchards, and anchovies are small fish of the herring family, often salted and smoked and then preserved in oil.

[3] In the past, fishing vessels were restricted in range by the simple consideration that the catch must be returned to port before it spoils and becomes worthless.

Refrigeration and freezing also allow the catch to be distributed to markets further inland, reaching customers who previously would have had access only to dried or salted sea fish.

They are designed to inhibit the activity of spoilage bacteria and the metabolic changes that result in the loss of fish quality.

[4] To flourish, bacteria need the right temperature, sufficient water and oxygen, and surroundings that are not too acidic.

[5] If the temperature is decreased, the metabolic activity in the fish from microbial or autolytic processes can be reduced or stopped.

There are key issues with fish cold store design and management, such as how large and energy efficient they are, and the way they are insulated and palletized.

It is a safe cooling method that keeps the fish moist and in an easily stored form suitable for transport.

It complies with HACCP and ISO food safety and public health standards, and uses less energy than conventional freshwater solid ice technologies.

In more recent times, freeze-drying, water-binding humectants, and fully automated equipment with temperature and humidity control have been added.

Cooking or pasteurizing does not completely inactivate microorganisms and may need to be followed with refrigeration to preserve fish products and increase their shelf life.

Sterilised products are stable at ambient temperatures up to 40 °C, but to ensure they remain sterilized they need packaging in metal cans or retortable pouches before the heat treatment.

This can improve preservation and reduce unwanted side effects such as the denaturation of nutrients by severe heat treatments.