Buy shellfish. The term shellfish covers a wide variety of species, but it is my favorite food grouping. Crustaceans have a chitinous exoskeleton, and shellfish are able to possess either chitinous or calcareous exoskeleton. The term shellfish encompasses lobsters, crayfish, crabs, shrimp, prawns, mussels, cockles, oysters, clams, cockles and scallops. The term crustacean specifically includes crab, shrimp, prawns and lobsters.
In the United States the most common and popular crabs are the Dungeness which is renowned for good meat quantity and sweet. The Snow Crab is also well known for its sweet and salty flavor, and the Alaskan King Crab with its delicious leg meat. Meanwhile back on the east Coast you cant go past Blue Crabs and I am addicted to soft shell crabs. A word of caution, if you catch your own make sure you comply with local laws on conservation and catch limits. Don’t retain egg bearing females and also observe size and catch limits.
If buying a crab anywhere in a seafood market check the crabs have a bright and metallic skin. Like fish the eyes should be clear and the gills should be moist with no slime or milky liquid present. The legs and claws should be attached with no damage to legs. The case should not have dents or fractures. If the crab doesn’t smell nice and briny or there is any trace of that ammonia smell don’t buy it. Always try and buy live crabs, always select once with a bit of zip and avoid those that appear sluggish and slow. Crabs should be heavy for their size, if it feels light then it probably is. Buy light ones and you are paying for shell. Try and keep your live crabs alive until cooking, to maintain freshness and stop the development of toxins that are contained within the greenish colored tomalley that lies within the crab’s digestive organ. While many find the tomalley a treat when used to make sauces and so on the FDA says don’t eat it. Given that this is the liver and pancreas equivalent always eat with caution, either on crabs or lobsters. Bacteria starts to release within a crab stomach very rapidly after death and these help decompose. So obviously it can affect the crab meat as well rather fast.
The same criteria apply for buying lobsters. Verify that there is no discoloration evident at the joints, and the shell should be intact, so watch out for shells that have cracks or fractures and indentations as this shows rough handling and can cause rapid spoiling. Best to buy live if you can. Also do the smell test.
Similar buying rules as the lobsters and crabs. Beware that thawed frozen being sold as fresh, its common and you need to ask. Check the shrimps for that sweet fresh briny smell. If you detect any odors, including the telltale ammonia smell then don’t buy. Also beware of chlorine smells as in some markets they use this to mask other off odors. Fresh shrimp will have a characteristic sweater or soft seaweed smell. They should look shiny and fresh with no discoloration on the legs or edges of segments. Make sure the shrimp and most and firm, ask to squeeze one. If it is rather dry and tough then its probably been frozen for some time. A mushy and soft texture is also a sign the shrimp is not fresh. Slime indicates it has also been frozen and also an indication that excess Sodium Tripolyphosphate has been used to reduce post freezing dehydration.
The shells should have that lovely translucent appearance and the shell has a glossy and firm appearance. The head should still have the antenna attached and this is an indicator they have not been frozen. Don’t buy shrimp or prawns that have missing or shrunken eyes, and eyes should be prominent and have a glossy and shiny appearance. Uncooked and raw shrimps and prawns have varying colors that range from green to brown and pale in-between. If a shrimp have a pink spot and white meat it can indicate incorrect icing and even partially cooking.
If you see black spots on in the shell they are no longer fresh. They should not have any slime or spots on the shell either. If you are lucky enough to buy live then pick out the active ones. Be careful of shrimp that shows yellowing near the tail or the swimmerets as this indicates excessive application of Sodium Bisulfate which is used to stop shrimp shells from melanosis or black spot which is the darkening of the head and shell after harvesting and exposure to oxygen. Fresh is always best when you buy shellfish and how to cook seafood.