Can I eat mussels if the shells are open before cooking?

it is a myth Mussel myth an open and shut case. To summarize, there are a small percentage (11.5%) of mussels that when tested will not relax its abductor muscles even after cooking. Whether a mussel opens or not after cooking is not an indication of freshness of the shellfish. read more

You can but I don't suggest it because the mussels are dead. Which means they are not fresh and aren't good to eat and you can get sick. If it's open tap the shell if it closes then your fine, if you can see in the shell before you cook it's no good and you should return them. read more