Shrimp are nutritious, delicious and quick to prepare. Having them in your freezer markedly increases your dinner options — they can enhance dishes such as scampi, paella, fried rice and gumbo. But if your frozen shrimp smells fishy or has freezer burn, it has spoiled and should be discarded.
Selecting and Storing Frozen Shrimp
You can either buy shrimp frozen, raw or alive. According to the Food and Drug Administration (FDA), if you purchase shrimp raw — whether your intent is to cook or freeze them once you get home — make sure the shrimp is kept over ice at the store and has a pearl-like color with little or no odor. Purchasing live shrimp is rare. But if you decide to go this route, check for leg movement to ensure the shrimp are still alive and have not begun spoiling.
According to the Auguste Escoffier School of Culinary Arts, frozen shrimp are actually fresher than "fresh" shrimp. This is because the frozen shrimp you see at the grocery store are usually thrown on ice immediately after they are caught or harvested and are kept frozen until they are sold. Shrimp that is sold raw on the other hand is most often frozen upon harvest, and then thawed before being sold. The raw shrimp have more time to spoil.
That being said, according to the FDA, frozen seafood can also spoil, especially if it is left at warm temperatures for too long before cooking. This can happen when shrimp thaws during transport from fishing port to grocery store or from grocery store to your home.
Signs to look out for are freezer burn on shrimp, torn or opened packaging and frozen shrimp that are bendable. Do not buy or use frozen shrimp if you notice any of these signs. Also, if you notice that the "use by" date on the packaging of your frozen shrimp has expired, discard the package and do not use.
Once home, store frozen shrimp in moisture-free, tightly sealed plastic, foil or paper. When ready to cook, thaw frozen shrimp gradually by putting in the refrigerator overnight, or seal it in a plastic bag and immerse in cold water if you need to cook it more quickly. If you're going to cook the shrimp immediately, you can put shrimp in the microwave and heat on the "defrost" setting until the shrimp is still icy but pliable.
Read more: Do Prawns Make a Healthy Meal?
Black Spots on Shrimp
If you find or are worried about black spots on shrimp, you have nothing to worry about if the spots are found on the shell. According to Louisiana Fisheries Forward, shrimp can occasionally have a discolored shell called black spot or melanosis.
This does not signify spoilage or the presence of bacteria. Instead, these black spots are caused by an enzymatic reaction between naturally occurring amino acids and sunlight. Shrimp with melanosis on the shell are still safe to eat. Some shrimp are processed with sulfites to prevent melanosis. If the shrimp you are purchasing have been processed with sulfites, this will be listed in the ingredient list, as sulfites are a known allergen.
If you are buying shrimp live and in the shell, you'll notice the head of the shrimp might start turning black once the shrimp are no longer alive. If this begins to happen, the meat of the shrimp is still fresh and safe to eat as long as only the head of the shrimp has darkened.
Read more: The Best and Worst Frozen Foods