Pasteurization is a preventive measure of public health. The quality of post pasteurized milk is tested by:: (A) Phosphatase test, (B) Methylene blue test, (C) Catalase test, (D) Oxidase test
Answer is A. Phosphatase test is based on the fact that raw milk contains an enzyme called phosphatase which is destroyed on heating at a temperature which corresponds closely with the standard time and temperature required for pasteurization. At 60 deg C for 30 minutes phosphatase is completely destroyed. Consequently, the test is used to detect inadequate pasteurization or the addition of raw milk. Other methods: Standard plate count and Coliform count. Ref: Park's Textbook of Preventive and Social medicine, 19th edition, Page 522.