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Molluscs
Molluscs is entry 14 of the fourteen substances Annex II of Regulation (EU) No 1169/2011 makes declarable. IgE-mediated food allergy, mainly to tropomyosin. Where it hides, which exemptions apply, and what it cross-reacts with.
This is reference information, not a diagnosis and not a treatment plan. A pollen calendar cannot tell you what you are allergic to, and no page can clear a food as safe for you — only the label on the packet in your hand and the clinician who knows your history can do that. Anything beyond mild, short-lived symptoms in the mouth or nose — swelling that affects breathing or swallowing, hives away from the mouth, wheeze, vomiting or faintness — is an emergency question, not a reading question.
What the law says
Annex II, entry 14: “Molluscs and products thereof”
That wording carries the whole obligation. The substance must be declared whenever it is used in the making of a food and is still present in the finished product, even in an altered form, and it must be picked out inside the ingredient list by typeset — bold, capitals, italics, underlining or a contrasting colour. There is no legal requirement for a separate allergen box, so the ingredient list is where to look.
Source: Regulation (EU) No 1169/2011, Annex II and Article 21 · checked 2026-09-06
What the reaction actually is
Molluscs are mussels, oysters, clams, scallops, squid, octopus, cuttlefish and snails. Like crustaceans they are dominated by tropomyosin, a heat-stable muscle protein, so cooking does not remove the allergen and cooking vapour can be enough to cause symptoms in a very sensitive person.
Who gets it, and does it last
Mollusc allergy typically presents in adulthood and typically persists. It is separated from crustaceans in the Annex because a person can be allergic to one group and tolerate the other, and a label that said only "shellfish" would not tell them which.
Where it hides
- Oyster sauce in Chinese cooking
- Seafood stock, paella and risotto bases
- Fish sauce blends
- Surimi products
- Some kimchi and Asian condiments
Molluscs are eaten far less here than in southern Europe, but mussels appear on restaurant menus across the region and oyster sauce is in most home kitchens that cook Chinese food. The rare-but-real exposure pattern makes it easy to go years between reactions and lose track of the cause.
Cross-reactions
Tropomyosin links molluscs to crustaceans and to house dust mite, so the mite-shellfish route applies here as well. Cross-reactivity between the mollusc classes — bivalves, gastropods and cephalopods — is common but not universal, which is why squid and mussel are tested separately.
The labelling detail
Entry 14, no exemptions. Oyster sauce and mollusc-derived stock are declarable however small a share of the recipe they are, and this is the entry that makes an ingredient list useful in a restaurant with an Asian menu.
Exemptions: none. Entry 14 has no carve-outs at all, so there is no processed fraction of it that escapes the label.
Precautionary wording — “may contain”, “made in a factory that also handles” — is a separate matter: it is voluntary, unstandardised and carries no threshold. How strictly to treat it is a clinical decision, not a reading of the label. The labelling explainer sets out the whole frame, including what happens in restaurants and bakeries where there is no pack at all.
What gets misread
The word "shellfish" is the problem. In everyday speech it covers two separate legal entries and two separate clinical problems, and someone who reacts to prawns may eat mussels safely, or the reverse. Only the specific name on the label answers it.
Sources: Regulation (EU) No 1169/2011, Annex II · Commission Implementing Regulation (EU) No 828/2014 (gluten claims) · WHO/IUIS Allergen Nomenclature · season windows from the national aerobiology monitoring programmes of Estonia, Finland, Sweden, Denmark and Norway · cross-reaction patterns paraphrased from the allergy literature and EAACI material · checked 2026-09-06
Frequently asked questions
Is molluscs one of the fourteen EU allergens?
Yes, entry 14. The Regulation words it as: Molluscs and products thereof. It must be declared and emphasised in the ingredient list of any food sold in the EU that contains it.
Where does molluscs hide?
The routine unexpected sources are oyster sauce in chinese cooking; seafood stock, paella and risotto bases; fish sauce blends; surimi products; some kimchi and asian condiments. This is what makes the ingredient list, rather than the name of the dish, the thing to read.
Are there any labelling exemptions for molluscs?
No. Entry 14 carries no exemptions, so any molluscs-derived ingredient is declarable however small the amount.
What does molluscs cross-react with?
Tropomyosin links molluscs to crustaceans and to house dust mite, so the mite-shellfish route applies here as well. Cross-reactivity between the mollusc classes — bivalves, gastropods and cephalopods — is common but not universal, which is why squid and mussel are tested separately.
Cereals containing gluten
Coeliac disease (autoimmune), wheat allergy (IgE) and non-coeliac wheat sensitivity — three different conditions under one entry.
Crustaceans
IgE-mediated food allergy, mainly to tropomyosin.
Eggs
IgE-mediated food allergy.
Fish
IgE-mediated food allergy, mainly to parvalbumin.
Peanuts
IgE-mediated food allergy — severe storage-protein type, or mild birch-pollen-related type.
Foods by diet and allergen
The food database filtered by written rules. A way to explore, never an allergen clearance.
Keep the log, spot the pattern
When a reaction is hard to pin down, a food and symptom log across weeks is worth more than any single meal you can remember. TempoLife keeps both in one place.