Pasteurization of milk is determined by: September 2005, 2007 & 2009

Ans. B: Phosphatase test Alkaline Phosphatase (ALP) is an enzyme naturally present in all raw milks, which is used as an indicator of proper milk pasteurization. Complete pasteurization will inactivate the enzyme to below levels which are detectable by conventional methods. Because the heat stability of ALP is greater than that of pathogens which may be present in milk, the enzyme serves as an indicator of product safety. The classic test for the determination of alkaline phosphatase activity is the Scharer Rapid Phosphatase Test. Turbidity test checks sterilisation of milk and distinguishes between pasteurized and sterilised milk. Methylene blue reduction test is done for determining ble bacterial count in the milk. Resazurin test is similar to Methylene blue reduction test but employs dye Resazurin in place of methylene blue.