For a variety of reasons, including preferences of taste and the possibility of food allergies, it’s a good idea to know which foods contain shellfish. Indeed, crustaceans are one of the eight major food allergens, the others being milk, eggs, fish, wheat, tree nuts, peanuts and soybeans. By law, the US Food and Drug Administration requires that any packaged food product with shellfish as an ingredient list the name of the shellfish on the label.