In canning, what temperature and time are recommended to kill botulinum?

• A. Heat to 212°F for 5 minutes.
• B. Canned food must be heated to 249°F for at least 3 minutes to kill botulinum.
• C. Heat to 180°F for 60 minutes.
• D. Heat to 300°F for 10 minutes.

Answer: (B)

Botulism risk in canned foods comes from spores of Clostridium botulinum, which are extremely heat resistant. Water boiling (around 212°F) doesn’t reach the level of heat needed to destroy those spores in low-acid foods. To reliably kill botulinum spores, you need the higher temperatures achieved with pressure canning, about 240–250°F, held long enough for heat to penetrate the food. The choice that states heating to roughly 249°F for at least 3 minutes fits that principle: a near-250°F temperature maintained for a short, adequate duration to achieve safe lethality. The other options don’t reach or sustain the necessary heat, so they aren’t reliable for killing botulinum in canned foods.