In the last post, it is suggested to siscard any mussels that look "dodgy". Not quite sure what "dodgy" means. But, I would never recommend anyone throws the dice with marine filter feeders.

Most, if not all, mussels in today's fish markets are carefully cultured in suspention farms...where consumer health is a major concern. They are safe to eat.

But, the term "dodgy" would worry me. IMO, never eat any filter feeding marine mulluska if there is any reason to suspect there is a quality (health) problem.