Application of gamma irradiation for the microbiological safety of sliced cheddar cheese

This study was conducted to establish the microbiological safety of sliced cheddar cheese with gamma irradiation. Total aerobic bacteria was 2.50 Log CFUg-1 in non-irradiated sample. No viable cells were observed in the gamma-irradiated at 1 kGy and over. D10 value for Listeria monocytogenes and Staphylococcus aureus inoculated in sliced cheddar cheese were 0.64 and 0.54 kGy, respectively. TBARS (2-thiobarbituric acid reactive substances) values were increased as irradiation dose was increased, but there was no significant difference between nonirradiated and irradiated samples at 1 kGy. Sensory evaluation showed there was no significant difference between samples irradiated at 1 kGy and non-irradiated in respect of color, odor, overall acceptability. Theses results indicated that gamma irradiation at 1 kGy was considered to be an effective treatment to ensure the microbiological safety of sliced cheddar cheese with minimal change of sensory, even though further studies should be investigated to reduce the deterioration of sensory quality induced by gamma irradiation