When I was a kid in the country, I knew several farm families who always served their main meal at noon. When it was over, dishes were covered but left on the table, and the evening meal was the same food, room temp. Houses generally weren't air conditioned, so this could mean six to eight hours in temps of over 80F. Don't remember anyone getting ill from it.
Not that I would try that now. I've occasionally left things out overnight that I intended to keep, but wine or getting sleepy got in the way. My rule of thumb is that if it's a cured meat, or pretty acidic (spaghetti sauce, vegetable soup), I'll chance it. Otherwise, it goes.
