Yes. Squid, octopus and cuttlefish are cephalopod molluscs and must be declared as molluscs under EU law.

Does oyster sauce contain molluscs?

Yes. Oyster sauce is made from oyster extract and must be declared as molluscs.

Can someone allergic to prawns eat mussels?

Some can and some cannot. Crustaceans and molluscs are separate allergens, but some people react to both because of similar proteins. The guest should follow their allergist's advice.

Is squid ink an allergen?

Yes. Squid ink is a mollusc product and must be declared.

Are snails a mollusc allergen?

Yes. Land snails, including escargots and Maltese bebbux, are gastropod molluscs and must be declared as molluscs under EU law. Some people allergic to dust mites or crustaceans also react to snails.

Mollusc allergy: squid, octopus, mussels, clams and the hidden sources on a menu

By the Menulta editorial team · Facts checked 15 October 2026 · Updated 15 October 2026

The short answer

A mollusc allergy is an immune reaction to proteins in molluscs: bivalves such as mussels, clams, oysters and scallops; cephalopods such as squid, octopus and cuttlefish; and gastropods such as snails and whelks. Molluscs are a separate allergen from crustaceans in EU law. They hide in squid ink pasta, oyster sauce, seafood stocks, paella, mixed fried seafood and some Asian condiments. Mollusc allergy can be severe and usually lasts for life.

What counts as a mollusc

Molluscs were added as the fourteenth Annex II allergen, after the original list, because reactions to them are common and can be serious. The group is broad and includes animals guests may not think of as 'shellfish' at all.

Mollusc groups and examples
Group	Examples
Bivalves	Mussels, clams, oysters, scallops, cockles, razor clams
Cephalopods	Squid and calamari, octopus, cuttlefish
Gastropods	Land snails (escargots), whelks, periwinkles, limpets, abalone

Molluscs and crustaceans are separate allergens

Everyday language puts squid, prawns and mussels together as 'seafood' or 'shellfish', but EU law separates crustaceans (entry 2) from molluscs (entry 14). Some people react to both, often because of similar tropomyosin proteins, and some react to only one. A guest who says 'I can eat prawns but not mussels' is describing a mollusc allergy, and the allergen record must let them choose.

Write 'molluscs (squid)' or 'molluscs (mussels)' in the record, not just 'shellfish'. That level of detail is what a guest with a specific allergy needs.

Hidden molluscs in restaurant dishes

Squid ink: used in black pasta, risotto nero and some breads and sauces.
Oyster sauce: a common base in Chinese and South-East Asian stir-fries and marinades.
Seafood stock and fumet: often made with mussel or clam liquor.
Paella, fideuà and seafood rice: almost always include squid, mussels or clams.
Fritto misto and mixed fried seafood: calamari in shared fryer oil.
Octopus salads and stews: common on Mediterranean and Maltese menus, including stuffat tal-qarnit (octopus stew).
Escargots and snail dishes, including Maltese bebbux.
Some fish sauces, seasonings and 'seafood flavour' snacks.

Molluscs on Maltese menus

Octopus and squid are central to Maltese seafood cooking. Stuffat tal-qarnit (octopus stew), fried calamari and stuffed squid (klamari mimlija) are common, and snails (bebbux) appear in some traditional dishes. Tourists may know these dishes by Maltese names only, so the allergen record should name the mollusc in plain words in each language rather than relying on the dish name.

Serving a guest with a mollusc allergy

Ask whether the guest also reacts to crustaceans or fish, then check every component, especially stocks, sauces and condiments. If the fryer is shared with calamari, fried food is not safe. Use separate pans and utensils and keep the dish away from the seafood station. With paella and other shared seafood dishes, the safest answer is usually to recommend a different dish rather than try to adapt it.

Why molluscs are easy to miss

Molluscs often appear as a supporting flavour rather than the main ingredient. Oyster sauce in a vegetable stir-fry, clam juice in a tomato-based cocktail such as a Caesar or Bloody Caesar, a spoonful of squid ink in a sauce, or a seafood stock in a risotto that is otherwise all vegetables: none of these dishes looks like seafood. Guests with mollusc allergy may order them without suspecting anything.

Bought-in condiments are a frequent route. Oyster sauce, some XO sauces and some Asian seasoning mixes contain mollusc extracts. Check every condiment label, and list each one as a recipe in the allergen record so that every dish using it is flagged automatically.

Questions to ask suppliers

Ask seafood suppliers to state clearly which products contain crustaceans, which contain molluscs and which contain fish, and whether mixed seafood products combine them. Ask condiment suppliers about oyster extract, clam juice and squid ink. Ask stock and sauce suppliers whether their seafood bases include mussels or clams. Keep the answers with your allergen record, separated by group so that a guest allergic to only molluscs gets an accurate answer.

Review the record whenever a supplier, a recipe or a seasonal special changes. Seafood menus change often, and molluscs tend to arrive with the specials.

Sources

This guide is general information, not medical or legal advice. Guests with an allergy should follow their doctor's advice. Operators should confirm their own setup with their food safety adviser or local authority.