I live a far distance from any body of salt water, so the only mussels available are packaged frozen mussels.

I have always heard that cooked mussels must open or they are not good to eat, but when we cooked the frozen mussels only a few opened. I went ahead and ate them anyways, they tasted fine and did not make me sick.

Is it normal for frozen mussels to not open their shells when cooked? If it is normal, is there a way to tell if they are safe to eat?

  • Thank you for the info. Had lived with the old wives tale forever.
    – user15358
    Jan 22, 2013 at 1:56

1 Answer 1


'You shouldn't eat mussels that don't open' is an unfounded myth. It was first mentioned in a book by the British food writer Jane Grigson in the 1970s and grew through repetition to the point that 90% of cook books mentioned it in the 1990s.

The fact is, mussels that don't open after cooking are more likely to be safe than those that do.

You should, however, be careful to remove any mussels that have opened before cooking, as they'll be dead and likely to make you ill.

  • This conflicts with what was said previously here cooking.stackexchange.com/questions/1168/… I am inclined to believe you though. Here is a link that supports your statement abc.net.au/science/articles/2008/10/29/2404364.htm
    – Wulfhart
    Jul 11, 2011 at 18:37
  • 2
    If the mussels are frozen prior to cooking they are most assuredly dead already. That brings the question, "Do already open frozen mussels need to be discarded?"
    – Wulfhart
    Jul 12, 2011 at 16:29
  • 1
    If they're fresh and open then it implies that they have been dead a while and thus have been rotting. While frozen ones are definitely dead, they are also A) frozen and B) closed, reducing the amount of bacteria involved considerably. Jul 12, 2011 at 19:29
  • 5
    I can't believe no one has mentioned this. That uncooked mussel that's suspiciously open? Give him a good tap. If he's alive, that will scare the little sucker, and he'll close. If he's still open, then he is trash.
    – Jolenealaska
    Sep 12, 2014 at 2:01

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