> Ive learned leaving soup out and reboiling is fairly common in some cultures which is unfortunate.

I know next to nothing about chemistry or biology but I do cook a lot of food, and quite often have leftovers.

After many years in Germany, I got into the habit of leaving food out, and that would mostly be fine. Very rarely would food spoil, at least from a culinary perspective (I'm not disputing the presence of bacteria or harm of its waste).

However after even a few months in Taiwan I learned that this strategy is basically impossible: food left outside spoils within hours.

Given I originally come from a country that is warmer, but much dryer than Taiwan, where food doesn't spoil if left out nearly as fast, I do believe it has to do more with humidity than with temperature.