Opened or Closed?
How to know when clams/mussels are safe to eat:
When purchasing fresh clams or mussels from the fish counter, the shells should be tightly closed. However, if you see any shells that are gaped open, it may simply be that the clams/mussels have been weakened from being out of water. Tap on the shell and if it pulls shut, the clam or mussel is still alive and ok to eat. If the clam or mussel does not respond, discard.
When cooking mollusks, the muscle relaxes and the clams pop open.
FYI – after you purchase clams/mussels, do not store them in a sealed bag, as they can suffocate. Place them in an uncovered bowl and refrigerate them until you are ready to prepare. Rinse thoroughly in the sink and if they feel gritty, brush them with a stiff plastic brush under running water. Use this prep time to check through the clams/mussels, discarding those open shells that remain so after tapping on shell. Also, if your shellfish smells like anything other than the ocean, it should not be consumed!According to our Experts, here's What’s in Season in our Seafood Department.