A laboratory determination of the destruction of α-amylase and salmonellae in whole egg by heat pasteurization

Abstract

The conditions of heating necessary to destroy salmonellae in liquid whole egg have been compared with those necessary to destroy the activity of the α-amylase of whole egg. All conditions of pasteurizing from the mildest at 61·1° C. (142° F.) for 1 min. to the most severe at 65·5° C. (150° F.) for 5 min. eliminated Salm. typhimurium . The heat-resistant strain of Salm. senftenberg N.C.T.C. 9959 (775 W) was not recovered after heating at 64·4° C. (148° F.) for 2½ min. and at the lower temperatures when the heating period was 3 min. or more. The activity of α-amylase was also destroyed by heating at 64·4° C. (148° F.) for 2½ min. but not at lower temperatures. Because the baking properties of egg are not impaired by heating at 64·4° C. (148° F.) for 2½ min. it is proposed that the inactivation of the α-amylase of whole egg can be used as a test for controlling the pasteurization process, and a routine test has been developed which can be completed within 1 hr.