Eli5 why is it that food can be left in steamers and under heat warming lamps for hours but it harbors harmful bacteria if you leave it in a hot place like a car for a few hours?
In higher temperatures bacteria reproduce faster, but once temperature hits about 65 °C (150 °F) they start dying because it’s too much heat for them. The inside of a car doesn’t get quite as hot as that, but gets sufficiently warm for bacteria to reproduce very fast. Food in steamers and under lamps does get hot enough to kill off bacteria.
there’s a danger zone where bacteria are most harmful
food under heating lamps are constantly kept at a temperature *above* the danger zone, where bacteria die
food left in a car rapidly hits the danger zone, where bacteria multiply
between 41°F and 135°F is known as the temperature danger zone, which is the perfect temp for dangerous bacteria to grow. hot steam tables keep foods above this temperature while a car sitting in the sun isnt always able to get above the temperature danger zone.
According to US food safety standards, there is the “Rule of 4”:
#Between 40 and 140 degrees Fahrenheit is safe for 4 hours.*
This applies to cars and heat lamps. Keeping food outside of that temp range is safe, as bacteria have difficulty operating/surviving.
*it’s technically between 41 and 135 degrees, but that’s harder to remember.
Because you’re underestimating how hot heat lamps and steam are. Or overestimating how hot a car is, but that seems less likely.