Influence of gamma irradiation on growth and survival of Escherichia coli O157:H7 and quality of cig kofte, a traditional raw meat product

Cig kofte is a traditional Turkish food containing raw ground meat. Samples inoculated with Escherichia coli O157:H7 were irradiated at 0.5-6 kGy with a 60Co source and stored at 4 and 25 °C. Total aerobic mesophilic count decreased with increasing irradiation doses, D10 value was 0.83 kGy. Escherichia coli O157:H7 count decreased from 5.1 log10 CFU g-1 to an undetectable level (<1 log10 CFU g-1) after 1-day storage at 4 °C following irradiation at 2 kGy, D10-value was 0.29 kGy. Irradiation doses up to 2 kGy did not affect sensory quality after 1 day. There was colour loss in samples irradiated at 2 kGy or above and stored for longer periods. Storage of the irradiated products at abused temperature must be avoided for safety assurance. Irradiation at 2 kGy has a great potential for extending the shelf-life of cig kofte and assuring safety by decreasing the number of E. coli O157:H7 and other bacteria, but further studies with suitable package designs are needed to decrease quality degradation during extended storage.