Microwave Treatment of Pasteurized Milk

Abstract

AbstractThe average shelf life of pasteurized fluid milk is 10.7 days. The purpose of this study was to examine the possibility of extending this with the application of microwave heat. This would be convenient for the growing number of small households. For these individuals, it is difficult to use a quart of milk in 10.7 days.Pasteurized homogenized milk in 200 ml lots was exposed to 2450 MHz microwave treatment. After 85, 97, 100 and 120 second treatments, the temperatures increased to 45°, 50°, 55° and 60°C respectively. Both Standard Plate Counts and Psychrotrophic Bacteria Counts were dramatically reduced with increasing temperatures. Psychrotrophs were reduced from a level of 1.8 × 106/ml to a nondelegable level when samples were brought to a temperature of 60°C. informal taste tests indicated that microwave-treated 8 day old pasteurized milk heated to a temperature of 60°C had a longer shelf life than the control and all other samples tested.