Heat does destroy most (including botulinum toxin), if not all bacterial toxins; the cdc.gov site (hardly casual about foodborne illenss; e.g it recommends throughly cooking sprouts) adresses the prevention of foodborne illness, both briefly, in their overviews (www.cdc.gov/foodsafety/diseases/) and in individual monographs, also available on their site. The thing is, just getting things hot doesn't do the trick: You need to keep a rolling boil for a decent chunk of time to be reasonably certain. And if something looks dodgy, it isn't worth taking chances. I buy as few tinned/preserved/vacuum-packed things as possible, and use them immediately. Then, if something looks like it's gone to hell, I go back to the shop with it (yeh, they love me), I've still got the receipt. The statement that heat does not destroy all food poisoning toxins is correct. http://en.wikipedia.org/wiki/Heat-stable_enterotoxin