Effect of High-Temperature Short-Time Heat Treatments on Some Properties of Milk. I. Inactivation of the Phosphatase Enzyme

Since the development of the phosphatase test by Kay and Graham (8) and its subsequent modifications, several studies have been made to determine the suitability of the test for detecting irregularities in the pastuerization of milk and other dairy products. The literature on this phase of the phosphatase test up to 1939 has been thoroughly reviewed by Burgwald (2). The reported studies showed that all raw milk contains phosphatase, that the thermal resistance of phosphatase is greater than that of pathogens, and that the test is sufficiently sensitive to detect important variations in pasteurizing conditions on the basis of the residual phosphatase activity. Other work has been directed toward improvement of the phosphatase test to make it more sensitive, more rapid, and more quantitative