Application of gamma irradiation for inactivation of three pathogenic bacteria inoculated into meatballs

In this research, the effect of gamma irradiation on the inactivation of Escherichia coli O157:H7 (ATCC 33150), Staphylococcus aureus (ATCC 2392) and Salmonella typhimurium (NRRL 4463) inoculated into Tekirdag meatballs was investigated. The meatball samples were inoculated with pathogens and irradiated at the absorbed doses of 1, 2.2, 3.2, 4.5 and 5.2 kGy. E. coli O157:H7 count in 1 kGy irradiated meatballs stored in the refrigerator for 7 days was detected to be 4 log cfu/g lower than the count in nonirradiated samples (p<0.05). S. aureus counts were decreased to 4 log cfu/g after being exposed to irradiation at a dose of 1 kGy. Although it was ineffective on elimination of S. typhimurium, irradiation at a dose of 3.2 kGy reduced E. coli O157:H7 and S. aureus counts under detectable values in the meatballs. However, none of the test organisms were detected in the samples after irradiation with 4.5 kGy doses.