Very few medically significant bacterial spores survive boiling temperatures. Clostridium botulinum (botulism) is the common one, and it prefers an anaerobic e

Very few medically significant bacterial spores survive boiling temperatures. Clostridium botulinum (botulism) is the common one, and it prefers an anaerobic environment (and other requirements: low salt and low acidity[1] — which is why home fermentation, done properly, avoids the risk) and not a lot of microbial competition, in order to get a foothold. Even if you ignore the standard recommendations, to refrigerate within 1-2 hours, and to toss refrigerated food after 4-5 days, contamination with less-hardy bacteria is far more likely if the food isn't sealed. You tend to have to go out of your way with unsafe canning[2] or fermenting[3] to get botulism poisoning. Food contamination is generally the result of airborne or insect-borne or utensil-borne microbes that are far less robust than botulinum. Typical contamination tends to occur after the food has been removed from heat, and has cooled enough so the microbes won't be killed almost instantly. Or, of course, if the food was improperly cooked and wasn't uniformly heated to sufficient temperature in the first place. [1] https://jfoodprotection.org/doi/pdf/10.4315/0362-028X-42.3.245 https://jfoodprotection.org/doi/pdf/10.4315/0362-028X-42.3.2... [2] https://www.cdc.gov/Mmwr/preview/mmwrhtml/mm6429a6.htm https://www.cdc.gov/Mmwr/preview/mmwrhtml/mm6429a6.htm [3] https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5032a2.htm https://www.cdc.gov/mmwr/preview/mmwrhtml/mm5032a2.htm