isn't it always safe to eat something if you heat it enough?

Yes, a temperature of <450,[sup]p[/sup]/[sub]3[/sub]> K will do nicely. :smiley:

For shame, any doper should know that the answer is

450 x (-1)^1/2 K

But isn’t that imaginary heat?

Don’t listen to him, ladies! I’m well worth your time.

By definition of “enough”, the answer is obviously yes.

Botulinum toxin, like the other posters have mentioned, can be destroyed at reasonable cooking temperatures. There are other toxins that won’t be destroyed by anything that leaves the food vaguely edible*, notably endotoxins. These molecules tend to be sturdy structural components of the bacteria. They’re not inherently toxic on their own, but the presence of a lot of bacterial components triggers your body’s “Intruder alert! Purge Digestive Track Immediately!” response.

Thus, food poisoning.

The trouble is that the most common forms of bacteria are the ones that make lots of endotoxins. Staphylococcus makes them, and it is guaranteed to be on your hands and everything you prepare in small amounts. If those small amounts are allowed to grow into large amounts, you end up with something that will give you food poisoning no matter how long you cook it. These bacteria grow rather slowly in the fridge, and not at all in your freezer (thus it’s safe to store something for a week or so in the fridge, and indefinitely in the freezer if it was prepared correctly). A few hours at room temperature can allow an awful lot of bacterial growth…

*By the time you’ve destroyed the endotoxins, you’ve also destroyed all of the carbohydrates, lipids, and proteins in your food. Which means you’ve ended up with ash, or a soup of small organic molecules. Mmm!

I’m going to share the suggestion of that Wikipedia page that you’re confusing endotoxin with enterotoxins, and enterotoxins are overwhelmingly still relatively heat-labile proteins. Please consider that human bowel contents are teeming with predominately Gram-negative bacteria, so I’m not sure that endotoxin is something novel and particularly pathogenic to the human GI tract, but I’m open to sources that say otherwise.
http://www3.interscience.wiley.com/journal/110531399/abstract

I wasn’t able to find a convenient source on the temperature and time required to denature toxins from S. aureus, B. cereus, etc. but they’re likely to be significantly less hardy than endotoxin.

British POW’s working on the Burma Railway in Thailand used to dig up meat that the Japanese soldiers had deemed was too rotten even for the prisoners (worms and everything), cook it thoroughly and eat it. But then again about a third of them died so actually I’m not sure what that proves…

Boy, talk about perpetuating negative stereotypes of British cooking…