Originally Posted by mcnerd
That will occur with bacteria growth and spoilage. It does NOT occur with the Botulism toxin.
That is not correct, mcnerd.
Botulism (Clostridium botulinum) is a gas producing organism. It is the same genus (Clostridium) that causes gas gangrene in wounds. It can and does bulge cans in many cases.
Logically, since botulism spores are one of the hardest organisms to destroy, if the can is bulging, you have to assume if it isn't botulism, then certainly it is something that survived a much lower processing pressure/temperature than what it takes to kill the botulism organism. so the botulism organism could well be present.
Although the toxin won't make the can bulge, the gas given off by the growth of the bacteria that produce the toxin surely can.
Any bulging can, therefore, is suspect and should be properly discarded.
mcnerd is correct in that you cannot tell for sure when you open the can if it contains botulism, and it is possible that a can can contain botulism toxin and not bulge.