system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can raw white mushrooms sit out for days, but have a room temp safe life of 3 hours once fried?

What's the difference? 

You've got raw white mushrooms and you can keep them out of the fridge for days and they'll be fine. 

But fry them in some oil (which doesn't need refrigeration) and suddenly the recommendation is 2-3 hours room temp before you run the risk of bacteria and food poisoning. 

Please explain, thanks!
gpt
If you watch a mushroom as you gently fry it, you'll see the point that it starts to produce moisture inside the cup.  That's caused by the cell walls breaking down, until then it's fairly robust and bacteria can't get in.