Common Foods Containing Shellfish
seafood flavoring (crab or clam extract)
Types of Shellfish
Because the main food served at a seafood restaurant is obviously seafood, it is best to steer clear of seafood restaurants. I used to be allergic to shellfish, and my family stayed away from seafood restaurants because of the high risk of cross contamination.
Mollusks vs Crustacea
Shellfish is generally categorized into two groups: mollusks and crustacea. When diagnosed with a shellfish allergy, it is possible to avoid one group and still eat foods from the other group.
Examples of mollusks include:
Examples of crustacea include:
For further information, the New York Times published an article that explains this idea well which you can read here