My girlfriend has done some work in Antarctica before, she said that it wasn't uncommon to find food ten or twenty years past its use-by-date. This is kind of the next level though.
The molecules that make up living things (e.g. corn or Spam) are stable at the temperatures at which those things live. If you remove the bacteria that primarily breaks things down there's not going to be much change.
It's no different than a house with 200yo timbers.