Eyes—bright, clear, and full Gills-reddish pink and free from slime Scales-adhering   tightly   to   the   skin,   bright colored with characteristic sheen Flesh-firm  and  elastic,  springing  back  when pressed,  not  separating  from  the  bones Odor-fresh, free from objectionable odors Fresh fillets, steaks, and chunks should also have a mild, fresh odor, and the flesh should have a fresh-cut appearance without any traces of browning or drying. Frozen  fish  compares  favorably  in  appearance, flavor, and food value with fresh fish and may be used interchangeably.  Frozen  fish  should  be  delivered  still frozen and should remain frozen until just before it is cooked. Frozen fish fillets and steaks should be thawed gradually  under  refrigeration  and  used  as  soon  as possible thereafter. The ideal temperature range for the thawing period is 36°F to 38°F. During the thawing period, the fish should be kept in the box just as it was received from the supplier. The box furnishes insulation that  permits  all  the  fish  to  thaw  uniformly.  If  not properly protected fish is thawed at temperatures that are too high, the surface may begin to spoil before the inside  is  completely  thawed.  Frozen,  breaded  seafood products should not be thawed before they are cooked. In general, a few helpful rules include the following: *    The amount of fish thawed should not exceed the amount  to  be  served. .   Fish should be thawed just before it is used; it should not be refrozen. .   Seafood products should not be thawed under cold  running  water. Shellfish Shellfish have a partial or complete shell covering. There are two classes of shellfish. Crustaceans have semihard to hard shells over the back and claws and soft shells under the body. Shrimp and lobster are examples. Mollusks have two very hard shells of the same size, which are tightly closed when the mollusk is fresh. Sort and discard any open shells before cooking. Clams, oysters,  and  scallops  are  examples. The chief varieties of shellfish available from Navy or commercial sources for use in the GM include clams, crabs, lobsters, crawfish, oysters, scallops, and shrimp. CLAMS.— Clams are procured as either frozen or canned minced. They are shucked and packed in natural juices.  Clams  are  available  as  either  frozen  regular  or individually quick frozen (IQF). They should not be thawed until they are to be used. IQF clams are easier to handle since only the amount needed is removed from the  container.  Once  removed,  they  should  not  be refrozen,  but  they  should  be  drained  and  used  in chowder. Canned clams should be drained and used like the frozen ones. CRAB LEGS.— Crab legs are a similar food item in flavor to lobster. The legs should be split before cooking. Steam or boil and serve with lemon wedges and drawn butter. CRAB MEAT.— Crab meat is available in tamed and frozen forms. It maybe used in crab cakes, salads, and  sandwiches.  Both  forms  are  fully  cooked  and  ready to use. Frozen crab meat, once thawed, should be used immediately.  Do  not  refreeze. LOBSTER.— Lobster is one of the largest species of shellfish. There are two types: northern lobster and spiny  lobster. Northern lobster, the true lobster, is distinguished  by  its  large  heavy  claws. Whole  lobsters  are  available  fresh  and  frozen. When cooked, the shell turns a bright orange-red color. Fresh and frozen lobsters are very perishable. Keep fresh lobsters alive until ready to use. Do not freeze. Frozen  whole  lobsters  are  commercially  available wrapped  in  polyethylene  film.  Do  not  thaw  before cooking.  Keep  frozen  at  0°F  or  below.  Follow  the AFRS for cooking directions. Be sure not to overcook or lobsters will be tough and dry. Spiny or rock lobster is distinguished by the absence of large claws and by the presence of its long slender antenna and many prominent spines on its body and legs. CRAWFISH.— Crawfish   or   lobster   tail   is sometimes  called  langosta  and  is  nearly  worldwide  in its   distribution,   ranging   through   the   tropical, subtropical,  and  temperate  waters  of  the  Atlantic, Pacific, and Indian Oceans. In the United States it is found in Florida and southern waters. The meat of the crawfish comes almost entirely from  the  tail.  The  frozen  tails  of  several  species weighing from 4 ounces to more than 1 pound each are sold on the market. OYSTERS.—  Shucked  oysters  are  those  that  have been  removed  from  the  shell.  Shucked  oysters  should be plump, have a natural creamy color, have a clear liquid (natural juices), and be free from shell particles. 6-18