Shellfish includes crustaceans (shrimp, lobster, crab) and mollusks (clams, mussels, oysters, scallops, squid). Live shellfish must stay alive until cooking.
Key idea
Live clams, mussels and oysters: shells closed, or they close when tapped; throw away any with cracked shells or that stay open. Store them cold (about 41°F or below) in a container that breathes, covered with a damp towel, never sealed airtight and never in fresh water. Restaurants keep the shellstock tag that comes with each container for 90 days after it is emptied, as the Food Code requires, so an outbreak can be traced.
- Cook clams, mussels and oysters until their shells open; discard any that stay shut.
- Shrimp, lobster and crab are done when the flesh is pearly and opaque.
- Debeard mussels just before cooking (pull the fibers toward the hinge).
- Crustacean shellfish is one of the nine major allergens; mollusks are a separate group.
Why it works
A live mollusk keeps its shell closed with a muscle. A dead one can't, and it may already be spoiling. The tag tells inspectors where and when the shellfish was harvested.
Worked example: Keep or toss?
A mussel is open and doesn't close when you tap it.
- It is probably dead.
Answer: Throw it away.
Safety
- Raw or undercooked shellfish carries a higher risk; restaurants that serve raw oysters must post a consumer advisory under the Food Code.
Common mistake
Storing live shellfish in a sealed plastic bag or in a bowl of tap water; both kill them.
Practice at home
- Buy a pound of mussels. Sort them (tap test), debeard them, and steam them with white wine and shallots until they open, about 4 to 6 minutes.
In Meal Prep
- Lobster Newberg: Delmonico's famous lobster dish