Actually no, .. the problem is that it DOESN'T get old.
Experiments have been done with fast food being left out at room temperature for months, even years, without decay.
That means even bugs won't eat it.
It's not even food.
Some
science people claim it's because it dries out quickly, thus inhibiting mold growth.
But the question wasn't "why doesn't it get moldy?". The question was "why doesn't it decompose?"
If you leave meat out, it decomposes mainly because of bugs & bacteria feeding on it. And then there's flies & maggots. Forensic detectives determine how long a corpse has been dead based on the growth stage of the bugs & larvae found feeding on it.
So they explained why it doesn't get moldy, but still haven't explained why it doesn't decompose & why bugs don't eat it.