The antibacterial system, lactoperoxidase-H2O2-SCN− was affected by the presence of heated milk or skim milk reconstituted from powders having received severe heat treatment. This inhibitory effect was related to the increase in exposed sulfhydryl groups and to the redistribution of protein between micellar and whey phases. Chromatographic analyses of heat-treated milk showed that the inhibitory factor was associated with the casein micelle fraction. The inhibition, however, was overcome by addition of unheated skim milk.
1Present address: Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden.
2Present address: Loughry College of Agriculture and Food Technoloy, Cookstown, U. K.
3Present address: Advisory and Development Service, Animal Production Department, University of Stirling, Stirling, U. K.