Question

Which test is used for checking pasteurization efficiency in milk processing plants?

• A. Risazurine test
• B. Phosphatase test
• C. Lipase test
• D. MBR test

Hint:

Remember: "Alkaline Phosphatase is the index enzyme of pasteurization."
If alkaline phosphatase is destroyed, you can confidently assume that all common vegetative pathogens in the milk have also been destroyed.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Pasteurization is a heat treatment process designed to destroy pathogenic microorganisms in milk.
To ensure the process has been executed effectively, quality control labs check for the inactivation of specific heat-sensitive enzymes naturally present in raw milk.
Detailed Explanation:
The alkaline phosphatase (ALP) enzyme is naturally present in all raw mammalian milk.
This enzyme has a heat resistance slightly greater than that of the most heat-resistant, non-spore-forming pathogens commonly found in milk, such as Coxiella burnetii and Mycobacterium bovis.
Because of this matching thermal death curve, the complete denaturation and inactivation of alkaline phosphatase serves as a reliable marker for successful pasteurization.
If the phosphatase test is negative (no enzyme activity detected), it confirms that the milk was heated to the required pasteurization temperature for the correct duration.
If the test is positive, it indicates under-pasteurization or contamination with raw milk.
In contrast:
- The Resazurin test and Methylene Blue Reduction (MBR) test are used to evaluate the overall microbial load and hygienic quality of raw or pasteurized milk.
- The lipase test is not a standard marker for pasteurization verification.

Step 2: Final Answer:
The test used to check pasteurization efficiency is the Phosphatase test.