This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Pasteurization is a preventive measure of public health. The quality of post pasteurized milk is tested by: \nSelect and explain. \nA. Phosphatase test, B. Methylene blue test, C. Catalase test, D. Oxidase test', 'role': 'user'}, {'content': "Answer: A \nExplanation: 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.", 'role': 'assistant'}]