242. A rapid phosphatase test: (a) Adaptation of Scharer's modification to pasteurizing conditions in Great Britain; (b) A study of factors influencing the reliability of the test

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Abstract
By adapting Scharer's “10min. field test” to British conditions of pasteurization, an accurate phosphatase test has been evolved requiring less than 1½ hr. for completion. The method is described in detail. A small percentage of anomalies was detected when applying the new method to the examination of pasteurized samples bulked from small quantities of milk (less than 100 gallons). This led to a study of several factors thought to be the likely cause of such anomalous results. No correlation was found between the phosphatase surviving heat treatment and the stage of lactation when milk from individual cows and from small groups of animals was tested, with the possible exception of the early stages of lactation when the enzyme concentration before and after heating was frequently found to be low. It was observed that pasteurized milk from animals suffering from mastitis tends to give abnormally high results of the phosphatase test. The amount of residual phosphatase is subject to considerable fluctuation.