Which statement about boiling-water resistance of C. botulinum spores is correct?

Which statement about boiling-water resistance of C. botulinum spores is correct?

• A. Certain spores survive 5-10 hours in boiling water
• B. All spores are instantly killed within a minute
• C. Spores killed within 5 seconds
• D. Boiling water has no effect on spores

Answer: (A)

The important idea here is that spores of Clostridium botulinum are extremely heat resistant, so simply boiling water doesn’t reliably destroy them. Boiling reaches about 100°C, which can kill many organisms, but many C. botulinum spores can survive extended exposure to boiling temperatures. In fact, some spores can endure boiling for hours, which is why boiling alone isn’t considered a safe sterilization method for foods that may support their growth. Because the spores can persist in boiling water, achieving inactivation in foods—especially low-acid foods stored in anaerobic conditions—requires higher heat achieved by pressure canning (reaching around 121°C) for appropriate times. That’s why the statement that certain spores survive 5-10 hours in boiling water best reflects reality. The other ideas aren’t accurate: spores are not instantaneously killed within a minute or seconds, and boiling water does have an effect but is not sufficient to inactivate all spores.

The important idea here is that spores of Clostridium botulinum are extremely heat resistant, so simply boiling water doesn’t reliably destroy them. Boiling reaches about 100°C, which can kill many organisms, but many C. botulinum spores can survive extended exposure to boiling temperatures. In fact, some spores can endure boiling for hours, which is why boiling alone isn’t considered a safe sterilization method for foods that may support their growth.

Because the spores can persist in boiling water, achieving inactivation in foods—especially low-acid foods stored in anaerobic conditions—requires higher heat achieved by pressure canning (reaching around 121°C) for appropriate times. That’s why the statement that certain spores survive 5-10 hours in boiling water best reflects reality.

The other ideas aren’t accurate: spores are not instantaneously killed within a minute or seconds, and boiling water does have an effect but is not sufficient to inactivate all spores.