Question

The index pathogen for heat treatment of milk is -

• A. Mycobacterium tuberculosis
• B. Coxiella burnetii
• C. Salmonella spp.
• D. Listeria spp.

Hint:

Alkaline Phosphatase (ALP) is a natural milk enzyme with a heat destruction profile slightly more resistant than that of Coxiella burnetii.
Therefore, the absence of active Alkaline Phosphatase in pasteurized milk serves as a reliable chemical marker to confirm successful pasteurization.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
An index pathogen is the most heat-resistant, non-spore-forming pathogen commonly found in a raw food material.
The thermal processing standards (like pasteurization) are designed specifically to ensure the complete destruction of this index pathogen.

Step 2: Detailed Explanation:
Historically, Mycobacterium tuberculosis (the causative agent of tuberculosis) was considered the index pathogen for milk pasteurization.
However, research established that Coxiella burnetii (the causative agent of Q fever) is more heat-resistant than M. tuberculosis.
Consequently, the thermal parameters for milk pasteurization—such as Low-Temperature Long-Time (LTLT) at \(63^\circ\text{C}\) for 30 minutes, or High-Temperature Short-Time (HTST) at \(72^\circ\text{C}\) for 15 seconds—were established to guarantee the complete elimination of Coxiella burnetii in raw milk.

Step 3: Final Answer:
The modern index pathogen for milk pasteurization is Coxiella burnetii, which corresponds to option (B).