The answer seems to be that while boiling water canning is pretty safe, pressure canning is modestly safer. The problem is that botulism is often fatal.

OTOH, meat infected with botulism is pretty rare other than certain kinds of fish and pork, IIRC.

It also seems to me that there are more cases of infant botulism from honey ingestion than there is from improperly canned meats.

It seems the risk is relatively low, but can be reduced even more by pressure canning.

I have often heard the statement that you cannot kill botulism spores in food by the application of temperatures at the boiling point of water, yet it is claimed this is adequate for disinfection of drinking water and 160-180 degrees is considered safe for cooking of meat.

I realize that botulism poisoning is the result of a toxin released as a side effect of the spore growing in your food, and not an infection. But it also possible to get botulism poisoning from ingesting contaminated meat or getting the spores in an open wound, so how is it safe to eat pork at 160 degrees?