Preservation

http://en.wikipedia.org/wiki/Food_preservation - Preservation  techniques are needed to prevent fish  http://en.wikipedia.org/wiki/Spoilage - spoilage  and lengthen  http://en.wikipedia.org/wiki/Shelf_life - shelf life . They are designed to inhibit the activity of spoilage  http://en.wikipedia.org/wiki/Bacteria - bacteria  and the  http://en.wikipedia.org/wiki/Metabolic - metabolic  changes that result in the loss of fish quality.  http://en.wikipedia.org/wiki/Meat_spoilage#Microbial_spoilage - Spoilage bacteria  are the specific bacteria that produce the unpleasant odours and flavours associated with spoiled fish. Fish normally host many bacteria that are not spoilage bacteria, and most of the bacteria present on spoiled fish played no role in the spoilage. ^{http://en.wikipedia.org/wiki/Fish_processing#cite_note-4 - [5]}  To flourish, bacteria need the right temperature, sufficient water and oxygen, and surroundings that are not too acidic. Preservation techniques work by interrupting one or more of these needs. Preservation techniques can be classified as follows. ^{http://en.wikipedia.org/wiki/Fish_processing#cite_note-FAO_preservation-5 - [6]}

[ http://en.wikipedia.org/w/index.php?title=Fish_processing&action=edit&section=5 - edit ]Control of temperature

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http://en.wikipedia.org/wiki/Ice - Ice  preserves fish and extends shelf life by lowering the temperature

If the temperature is decreased, the metabolic activity in the fish from  http://en.wikipedia.org/wiki/Microbial - microbial  or  http://en.wikipedia.org/wiki/Autolytic - autolytic  processes can be reduced or stopped. This is achieved by  http://en.wikipedia.org/wiki/Refrigeration - refrigeration  where the temperature is dropped to about 0 °C, or  http://en.wikipedia.org/wiki/Frozen_food - freezing  where the temperature is dropped below -18°C. On fishing vessels, the fish are refrigerated mechanically by circulating cold air or by packing the fish in boxes with ice.  http://en.wikipedia.org/wiki/Forage_fish - Forage fish , which are often caught in large numbers, are usually chilled with refrigerated or chilled seawater. Once chilled or frozen, the fish need further cooling to maintain the low temperature. 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  http://en.wikipedia.org/wiki/Pallet - palletized . ^{http://en.wikipedia.org/wiki/Fish_processing#cite_note-FAO_preservation-5 - [6]}

An effective method of preserving the freshness of fish is to chill with ice by distributing ice uniformly around the fish. It is a safe cooling method that keeps the fish moist and in an easily stored form suitable for transport. It has become widely used since the development of mechanical  http://en.wikipedia.org/wiki/Refrigeration - refrigeration , which makes ice easy and cheap to produce. Ice is produced in various shapes; crushed ice and ice flakes, plates, tubes and blocks are commonly used to cool fish. ^{http://en.wikipedia.org/wiki/Fish_processing#cite_note-FAO_handling-2 - [3]}  Particularly effective is  http://en.wikipedia.org/wiki/Slurry_ice - slurry ice , made from micro crystals of ice formed and suspended within a solution of water and a  http://en.wikipedia.org/wiki/Freezing-point_depression - freezing point depressant , such as common salt. ^{http://en.wikipedia.org/wiki/Fish_processing#cite_note-6 - [7]}

A more recent development is  http://en.wikipedia.org/wiki/Pumpable_ice_technology - pumpable ice technology . Pumpable ice flows like water, and because it is  http://en.wikipedia.org/wiki/Homogeneous - homogeneous , it cools fish faster than fresh water solid ice methods and eliminates freeze burns. It complies with  http://en.wikipedia.org/wiki/HACCP - HACCP  and  http://en.wikipedia.org/wiki/ISO - ISO  food safety and public health standards. Finally, it uses less energy than conventional fresh water solid ice technologies. ^{http://en.wikipedia.org/wiki/Fish_processing#cite_note-7 - [8] http://en.wikipedia.org/wiki/Fish_processing#cite_note-8 - [9]}