Freezing Technology

6.3.1 Fresh fish

The important factors in the distribution of fresh fish are speed, cleanliness and the need to keep the fish well chilled. The fish must not be handled repeatedly.

Everything likely to come into contact with the fish has to be clean. Bacteria may be picked up from dirty surfaces, tools, uniforms and hands. This will accelerate, fish spoilage and may endanger public health. Fish boxes, trucks, loading platforms have to be cleaned and disinfected before use.

For shipping fresh fish, refrigerated transport is required. Temperature is the single most important factor influencing fresh fish spoilage. Chill fresh fish with ice immediately and keep it cool. Mix the fish and ice well. Ice must always remain in sufficient quantities for effective chilling and to separate the fish from each other and from the supporting surfaces. The air temperature in the container should be 2-3⁰C to allow the ice to melt slowly.

Fresh Fish Spoilage

• Coldwater fish spoils faster than warm water fish.
• Fatty fish spoils faster than lean fish.
• Smaller sized fish spoil faster than larger fish of the same species.
• Round fish spoils faster than flat fish.
• Shark spoils faster than lean fish.

Fresh Fish Fillets

Direct contact between fillets and ice is not recommended. Water will soften the texture and affect appearance. Separate the ice from the fillets e.g. by using plastic sheeting. Be sure to chill the fillets properly before packing. Chilling after packing is difficult because of the tightly packed mass of fish flesh.

Frozen Fish

            For shipping frozen fishery products refrigerated transport is required. The cold chain has to be maintained at all times. The normal working temperatures in modern cold stores for quick frozen foodstuffs are -30 to -25⁰C. Retail cabinets, in which the product should be stored for no more than a few weeks, usually operate at about -18⁰C or a little lower.

         Do not try to freeze fresh produce or try to lower the temperature of frozen fish when shipping. Prior to shipment always check the product temperature with a thermometer. Frozen fish should be handled with care. Rough handling, such as throwing, will cause the frozen flesh to crack, damage the skin and fins and these defects will inevitably show up when thawed.