Modeling the γ-irradiation inactivation kinetics of foodborne pathogens Escherichia coli O157:H7 , Salmonella, Staphylococcus aureus and Bacillus cereus in instant soup

The objective of the present study was to assess the inactivation kinetics of γ-irradiation of selected foodborne pathogens in instant soup. O157:H7 (ATCC 25922), subsp. serovar Enteritidis (ATCC 13076) (ATCC 2592), and (ATCC 11778) were inoculated into instant soup and irradiated at various doses of 0 (control), 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, and 10.0 kGy using Co source. The radiation response of these four major foodborne disease pathogens in instant soup was tested. As expected, the pathogen population decreased with increasing irradiation dose. By comparing bacterial resistance in instant soups according to D values, O157: H7 was the most radio-resistant bacteria (D of 1.580 kGy), followed by (D of 1.160 kGy), (D of 0.775 kGy), (D of 0.462 kGy). For modeling of inactivation kinetics, both, the conventional first-order linear model and Weibull model were compared and the goodness of fit of these models was investigated. Weibull model produced a better fit to the data. This research has shown that γ-irradiation was effective to eliminate pathogens in instant soup and it can be a great way to assure the microbiological safety of the instant soup.