Application of Gamma Irradiation for Eliminating Bacterial Contamination of Bovine Colostrums

In order to colostrum pasteurization and creating of dose-response curve for Escherichia coli and Staphylococcus aurous, the colostrum of cow was gamma irradiated at doses of 0, 0.5, 1 and 2 KGy. Chemical composition, true protein, electrophoretic pattern of proteins, lactose content, peroxide level and pH of colostrums samples before and after of irradiation were determinate. The obtained data were analysed using proc GLM of SAS software appropriate for completely randomized design. The effect of irradiation was significant on Escherichia coli and Staphylococcus aurous contamination of colostrums (p0.05) on chemical composition, true protein, fatty acid composition, peroxide level, pH and electrophoretic pattern of proteins and lactose content. Based on the results of this study, the appropriate dose for decrease in log cycle of Escherichia coli and Staphylococcus aurous population in colostrum is 0.68 and 1.15 kGy respectively. Therefore, gamma irradiation at low doses can eliminate Escherichia coli and Staphylococcus aurous contamination without negative impact on colostrum quality.