Whenever I buy frozen vacuum-sealed fish, the package clearly instructs me not to thaw the fish without removing it from the vacuum seal. This makes sense in a hazy intuitive way if I think about anaerobic bacteria like botulinum.

However, the frozen vacuum-sealed meat I buy has no such warning. For example, Omaha Steaks explicitly suggests thawing meat in the vacuum-sealed packaging.

I can't think of any reason why one would be OK if the other isn't. Is this a regulatory quirk, or is there a genuine reason why the correct thawing procedures are different?


1 Answer 1


Packaged fish is commonly known to contain Clostridium botulinum, either because its habitat generates the bacteria, or because of exposure somewhere between where the animal dies and your dinner plate.

Clostridium botulinum only causes illness if it can produce the botulinum toxin, and botulinum develops only at specific temperatures and in an anaerobic (there is little to no oxygen present) environment.

Botulism can cause death.

So, to eliminate risk of illness or death, avoid thawing your fish in an intact vacuum package.

  • This might help with context: skeptics.stackexchange.com/questions/52646/…
    – moscafj
    Dec 18, 2021 at 13:49
  • FAO says C. botulinum is commonly found in fish intestines, gills and oceanic muds.
    – bob1
    Dec 18, 2021 at 20:42
  • there is no guarantee that thawing under vacuum will actually cause botulism. however, when fish are filleted there can be cross contamination, so the warnings are used so that people can not claim they didn't know the better procedure to be followed, which could then lead to frivolous litigation (as is the habit in some countries) for not being warned.
    – Mr Shane
    Dec 18, 2021 at 20:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.