Fish lasts nearly twice as long in a 32ºF/0ºC slush as it does at typical refrigerator temperatures of 40–45ºF/5–7ºC It’s desirable to keep fish on ice as continuously as possible: in the market display case, the shopping cart, the car, and in the refrigerator Fine flake or chopped ice will make more even contact than larger cubes or slabs Wrapping will prevent direct contact with water that leaches away flavor In general, well iced fatty saltwater fish — salmon, herring, mackerel, sardine — will remain edible for about a week, lean coldwater fish — cod, sole, tuna, trout — about two weeks, and lean warm-water fish — snappers, catfish, carp, tilapia, mullets — about three weeks A large portion of these ice-lives may already have elapsed before the fish appear in the market Freezing To keep fish in edible condition for more than a few days, it’s necessary to lower its temperature below the freezing point This effectively stops spoilage by bacteria, but it doesn’t stop chemical changes in the fish tissues that produce stale flavors And the proteins in fish muscle (especially cod and its relatives) turn out to be unusually susceptible to “freeze denaturation,” in which the loss of their normal environment of liquid water breaks some of the bonds holding the proteins in their intricately folded structure The unfolded proteins are then free to bond to each other The result is tough, spongy network that can’t hold onto its moisture when it’s cooked, and in the mouth becomes a dry, fibrous wad of protein So once you’ve brought frozen fish home, it’s best to use it as soon as possible In general, the storage life of fish in ordinary freezers, wrapped tightly and/or glazed with water to prevent freezer burn (freeze the fish, then dip in water, refreeze, and repeat to build up a protective ice layer) is about four months ... proteins in fish muscle (especially cod and its relatives) turn out to be unusually susceptible to “freeze denaturation,” in which the loss of their normal environment of liquid water breaks some of the bonds holding the proteins... in their intricately folded structure The unfolded proteins are then free to bond to each other The result is tough, spongy network that can’t hold onto its moisture when it’s cooked, and in the mouth becomes a dry, fibrous wad... and in the mouth becomes a dry, fibrous wad of protein So once you’ve brought frozen fish home, it’s best to use it as soon as possible In general, the storage life of fish in ordinary freezers, wrapped tightly and/ or glazed with