Recognise the group behind the menu name
ASCIA’s shellfish guide lists abalone, clams, cockles, mussels, oysters, scallops, squid and octopus among shellfish to recognise. Its combined guide also includes crustaceans; Australian and New Zealand allergen declarations, however, require crustacean and mollusc as separate names. That labelling distinction can help frame a precise question. [1, 2]
The mollusc allergy guide is the broader overview. If your specialist has given species-specific advice, use that advice. This article does not decide whether someone who reacts to one mollusc can eat another, or whether they must also avoid crustaceans or fish.
Ask what a menu means by ‘seafood’ or ‘shellfish’ when the exact species matters. A seafood mix can change by supplier and season, so a past visit cannot confirm a current serving.
Prepared sauces need their own ingredient check
ASCIA advises checking oyster sauce, seafood flavourings, stocks, Asian soups and marinara-style sauces for shellfish. A sauce name is only a lead: a product marketed as oyster sauce can have a complex recipe, and a restaurant may use a purchased bottle or an alternative formulation. [1]
Ask to see the label of the actual sauce and whether it is added to the wok, marinade or finishing glaze. Check broths and premade seafood bases separately. Squid, oyster and mussel ingredient records can help with names, but they cannot verify a venue’s sauce.
A dish without visible shellfish can still use a shellfish stock or sauce. Conversely, a dish name associated with shellfish does not prove which species is in this version; ask the kitchen rather than guessing.
Labels and kitchen handling answer different questions
In Australia and New Zealand, mollusc must be declared when present in an applicable food, separately from crustacean. For food sold without a required label, allergen information must be displayed with the food or available on request. Precautionary ‘may contain’ statements are a separate, voluntary matter under the Food Standards Code. [2]
At a seafood restaurant, ask how mollusc dishes share grills, fryers, knives, chopping surfaces or serving tongs with your order. ASCIA specifically flags shellfish contact through fish-and-chip-shop oil. A written ingredient answer does not explain preparation. [1]
A useful question is: ‘Could you check whether this exact meal, its sauce and stock contain oyster, mussel, clam, scallop, squid, octopus or another mollusc, and how it is prepared around shellfish?’ If staff cannot check, leave the answer unconfirmed. The restaurant questions guide can help.
A change of sauce is a new recipe
If staff offer to omit oyster sauce or swap it for another seasoning, ask what is in the replacement and whether it was used earlier in a marinade or stock. Check any bought-in product from its current bottle, not a remembered brand description. A clean-pan request also needs an answer about the ladle, knife and plating area. [1]
The distinction between mollusc and crustacean declarations is useful when reading an Australian pack, but it does not by itself address transfer in a shared kitchen. Ask about the exact food and preparation whenever you dine out. [2]
Record a clear answer with the menu item, venue and date. Recheck on a later visit because suppliers and staff can change.
Sources & references
Source pages checked 18 October 2026. Confirm the exact current recipe and preparation with the venue.