All of the following methods are used to test pasteurization of milk except:-
**Core Concept**
Pasteurization of milk is a process that kills harmful bacteria and extends the shelf life of milk. It involves heating the milk to a specific temperature for a certain period to inactivate pathogens. The goal of pasteurization testing is to verify that the milk has reached the required temperature for the specified time.
**Why the Correct Answer is Right**
To test pasteurization, methods such as the "Standard Temperature Test" (A) and the "Plate Count Test" (B) are used. The Standard Temperature Test involves heating a sample of milk to 63°C (145°F) for 30 minutes to inactivate all bacteria, while the Plate Count Test involves incubating the milk on agar plates to count the number of bacteria present. Another method is the "Phosphatase Test" (C), which measures the activity of the enzyme alkaline phosphatase, which is present in raw milk but inactivated by pasteurization.
**Why Each Wrong Option is Incorrect**
* **Option D:** There is no widely recognized method of testing pasteurization by "Milk pH" measurement. Pasteurization does not affect the pH of milk significantly, and pH measurement would not be a reliable indicator of pasteurization.
**Clinical Pearl / High-Yield Fact**
The most common methods used to test pasteurization of milk include the Standard Temperature Test, Plate Count Test, and Phosphatase Test. These tests help ensure that the milk has been heated to a safe temperature to inactivate harmful bacteria.
**Correct Answer:** D