Phosphatase test in milk is done to know -

Tests of pasteurized milk (1) Phosphatase test : This test is widely used to check the efficiency of pasteurization. The 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. (2) Standard plate count : The bacteriological quality of pasteurized milk is determined by the standard plate count. Most countries in the West enforce a limit of 30,000 bacterial count per ml of pasteurized milk. (3) Coliform count : Coliform organisms are usually completely destroyed by pasteurization, and therefore, their presence in pasteurized milk is an indication either of improper pasteurization or post-pasteurization contamination. The standard in most Countries is that coliforms be absent in 1 ml of milk Ref: Park 25th edition Pgno : 692