Question

If the DRT for C.botulinum at $121^\circ C$ is 0.25, then for 12 D process, the time required for heating at $121^\circ C$ is .........minute.

• A. 2
• B. 3
• C. 4
• D. 1

Hint:

The "Botulinum Cook" is always $F_0 = 3$ min. This is a foundational constant in thermal processing. If you see $D = 0.25$ and $12D$, the answer is always $3$.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks for the calculation of total heating time (\(t\)) required to achieve a "12D" reduction of Clostridium botulinum at a constant temperature of \(121^\circ C\), given its Decimal Reduction Time (\(D\)-value).
Key Formula or Approach: The relationship between total heating time, the number of log reductions (\(n\)), and the D-value is: \[ t = n \times D \]

Step 2: Detailed Explanation:

• The Decimal Reduction Time (\(D\)-value) is defined as the time required at a specific temperature to destroy 90% of the microbial population (a 1-log reduction).

• Clostridium botulinum is the most significant pathogen in canning because it is an anaerobic spore-former. The industry standard for safety in low-acid canned foods is the "12D concept," which aims for a 12-decimal reduction in its population.

• Given Data:
- Temperature = \(121^\circ C\) (reference temperature).
- \(D\)-value at \(121^\circ C\) (\(D_{121}\)) = 0.25 minutes.
- Number of reductions required (\(n\)) = 12.

• Calculation:
\[ t = 12 \times 0.25 \] \[ t = 3.0 \text{ minutes} \]
• This 3-minute period is known as the "minimum botulinum cook" or the \(F_0\) value. It ensures that the probability of survival is reduced to less than \(10^{-12}\).

Step 3: Final Answer:
The time required is 3 minutes.