- Feb 4, 2013
- 28,175
I was always under the impression that they lasted forever under any circumstances but these new MRE have expiration dates!!!!!!
Because MREs are not canned.
In canning, the contents are cooked in the can and it is sealed. So the cooking kills the bacteria, and the sealed can prevents any more from getting in.
And the lack of oxygen prevents more spoilage bacteria from growing if they are in there.
Botulism actually needs a total lack of oxygen to grow. And that is the one worry of canned goods. But it is the reason you pressure cook in home canning, to get the temperature high enough to kill botulism.