Harmful bacteria such as salmonella and E. coli are a different story, though. When these baddies contaminate food, they do so without any physical signs, smells or tastes whatsoever. We need to rely on other methods to avoid getting sick.
Like killing the little beasties — which is really not that hard to do. Temperatures hotter than 165°F kill most bacteria within a few seconds. But to do the job, it's a food's internal temperature that has to reach 165°F, not just the outside. And with the exception of poultry, cooking meats or vegetables to that degree renders them all but inedible.
Fortunately, we have size on our side. Bacteria are really small, and it takes quite a lot of them to make us sick. So rather than killing them, and ruining our food in the process, we merely have to stop them from multiplying — or at least slow them down — so that there's never enough of them to do us any harm. We do that by controlling the food's temperature during every stage of storage and preparation. Bacteria won't multiply in the colder temperatures of a refrigerator or freezer, or at temperatures hotter than 141°F. Where they thrive is between 41°F and 140°F, a region known as the "Food Temperature Danger Zone."To substantially reduce your chances of contracting, or passing along, a food-borne illness, make sure that your perishable foods never spend more than an hour in the Food Temperature Danger Zone. Here are some basic food handling techniques to help you do just that.
And here's a table showing the key temperatures of the Food Temperature Danger Zone.