Freezing techniques

Three processes and how they affect your seafood.

For the majority of operators, buying frozen fish and shellfish can put quality and variety on the table all year long from top fishing grounds as far apart as Iceland, Alaska and Australia.

"Given advancements in freezing technology and improved handling requirements on fishing vessels and in processing plants, a lot of frozen seafood is actually better and closer to its live, natural state than if it were delivered 'fresh,'" says John van Amerongen, marketing communications specialist with Trident Seafoods. "Correct handling, timely freezing and careful glazing can suspend high-quality seafood at its peak of freshness."

The industry uses three primary freezing methods, described in descending order of quality and cost:

Frozen at sea is "the Rolls Royce"of processing, says Tom Sherman, VP of marketing for Icelandic USA, a seafood company. The fish is cleaned, water-glazed and quick-frozen in modern processing facilities on board the trawler within hours after it's caught. At the plant, the product is individually quick frozen (IQF) and packed, never breaking the cold chain.

Land frozen seafood is gutted and iced down on the boat, then processed on shore. Fillets are glazed and individually frozen before packing and storing in temperature-controlled warehouses.

Block frozen fish is also processed on land; the fish are machine filleted and frozen solid in a block of ice, causing some breakage and deterioration in processing and thawing.