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?
'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.
