EFFECT OF MICROWAVE RADIATION ON THE VIABILITY OF ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS

Abstract

Sterilization and decontamination of food like dairy products from bacteria that cause food poisoning is the paramount goal of food industry. Recently microwave ovens have been widely used for heating of food. This study was carried out in order to show the effect of microwave radiation on the viability of E.coli and Staphylococcus aureus in the milk. Known concentrations of E.coli and Staph,aureus in the local sheep milk were exposed to microwave radiation at 40%, 80% and 100% power levels at different time durations in seconds (0,5,30,60,120) and 0 time regarded as a control. A significant reduction in the number of colonies was detected with increasing the time of exposure for three power levels of microwave radiation compared to control. The killing effect of radiation was more associated with increasing the power level and time of exposure, in which the percentages of bacterial reduction were 12.1, 48.4 and 95.1 for E. coli at power level 40%,80% and 100% respectively while for Staph. aureus were 55.9, 92.7 and 80.7. Staph. aurues. The reduction percentages of E. coli after 120 seconds of exposure to power levels 40%,80% and 100% were 96.6, 100.0 and 98.7 respectively, while for Staph. aureus were 82.5, 99.08 and 99. It can be concluded from the results of this study that microwave radiation can be used as effective method for removing of bacteria that can cause food poisoning.