510. Reactivation of milk phosphatase following heat treatment. I

Abstract

1. Commercial samples of milk of Swiss origin, sterilized by rapid heating to high temperatures, developed a positive phosphatase reaction on storage. 2. The optimum temperatures of storage for the development of this positive phosphatase reaction was 30° C. 3. These commercial samples were sterile when received and remained sterile during storage. 4. The developed phosphatase is apparently identical with the normal alkaline phosphatase of raw milk as judged by ( a ) heat stability, ( b ) p H optimum and rate of hydrolysis at different pHs, ( c ) comparison of results by Kay-Graham and Aschaffenburg & Mullen tests.