Question

Given below are two statements:
Statement (I): The time-temperature combination of pasteurization that kills Coxiella burnetii typically involves heating milk to at least 63°C (145°F) for at least 30 minutes, or heating it to 72°C (161.6°F) for at least 15 seconds.
Statement (II): The time-temperature combination of pasteurization that can make the alkaline phosphatase test positive in pasteurized milk.
In light of the above statements, choose the most appropriate answer from the options given below.

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

A negative alkaline phosphatase test is the gold standard used to confirm that milk has been successfully pasteurized. A positive test indicates pasteurization failure.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Pasteurization is a heat treatment designed to eliminate all pathogenic vegetative bacteria in milk. The effectiveness of pasteurization is monitored using the alkaline phosphatase (ALP) test.

Step 2: Detailed Explanation:
Let us analyze both statements:

• Statement (I): Coxiella burnetii is the most heat-resistant, non-spore-forming pathogen found in raw milk. The standard pasteurization protocols—LTLT (Low Temperature Long Time: \(63^\circ\text{C}\) for 30 minutes) and HTST (High Temperature Short Time: \(72^\circ\text{C}\) for 15 seconds)—were specifically designed to ensure the destruction of this pathogen. Thus, Statement (I) is Correct.

• Statement (II): Alkaline phosphatase is a natural milk enzyme that is slightly more heat-resistant than Coxiella burnetii. Proper pasteurization completely denatures and inactivates this enzyme. Therefore, properly pasteurized milk should test negative for alkaline phosphatase. A positive test indicates under-pasteurization or contamination with raw milk. Thus, Statement (II) is Incorrect.

Step 3: Final Answer
Statement (I) is correct, but Statement (II) is incorrect.