Mollusks

Mollusks (molluscs in EU labeling) are soft-bodied sea and land animals, many of them with a shell. In food they include bivalves such as mussels, clams, oysters, scallops and cockles; snails, whelks and abalone; and squid, octopus and cuttlefish. Some people are allergic to mollusks, and cooking does not destroy the proteins that cause it.

How to use it

The EU and the US treat mollusks differently:

• In the EU and the UK, mollusks are one of the 14 allergens. They must be emphasized in the ingredients list, and restaurants must be able to tell you if a dish contains them.
• In the US, only crustaceans count as a major shellfish allergen. Mollusks appear by name in the ingredients list, but not in the "Contains" statement, and a US label will not emphasize them.

Some people who react to crustaceans such as shrimp and crab also react to mollusks, and some react to only one group. An allergist can tell you what you need to avoid.

Common mistakes

• Missing oyster sauce. It is in many Chinese and Southeast Asian stir-fries, marinades and noodle dishes.
• Forgetting squid ink, which colors black pasta and rice.
• Assuming a seafood mix is only fish and shrimp. Most also contain squid and mussels.
• Trusting a US label to warn you the way an EU label does.
• Sharing pans, fryers or cooking water with shellfish.

In recipes

Mollusks are central to many coastal dishes: paella, moules marinières, clam chowder, spaghetti alle vongole, fried calamari, grilled octopus and French escargots. Recipes for oysters and clams often start by shucking them. Dried scallops flavor XO sauce, and clam juice is used in some seafood stocks and drinks.

If you have a mollusk allergy, read labels every time you buy, ask in restaurants how dishes are made, and talk to a doctor about a plan for accidental exposure.