An inactivation kinetics model for Campylobacter jejuni on chicken meat under low-temperature storage

Campylobacter jejuni is susceptible to low temperatures. Freezing and chilling are effective interventions for reducing the occurrence of C. jejuni on poultry meat. The survival rates of three C. jejuni strains (ATCC33560, JR0706-2, and ALM-80) inoculated onto chicken meat samples were measured at -20°C and 4°C, and the survival curves of these three strains were determined. The results showed that the number of surviving cells decreased by 3.16, 2.87, and 3.14 log colony-forming unit (CFU)/g, respectively, at -20°C during the 55-day storage period. The survival curves showed that the mean inactivation speeds were slow in the initial 20 days of storage at -20°C, dropped rapidly between 25 and 45 days, and reached a plateau in reduction between 45 and 55 days. The number of surviving cells during the 10-day storage period at 4°C decreased by 3.47, 3.35, and 3.51 log CFU/g, respectively. The mean inactivation speeds at 4°C were 0.347, 0.355, and 0.439 log CFU/day. There were some differences in the inactivation speeds of the three strains of C. jejuni, but there was no significant difference in the trend of inactivation among the strains (p>0.05). Only the seven parameters are different for the strains originating from diverse sources when the inactivation trend was determined using a formula. Data-fitting software, MATLAB, was used to fit the survival rates data. The results showed that the established inactivation kinetics function fit the data well for the three different strains stored at -20°C and 4°C. This study revealed the inactivation kinetics for three C. jejuni strains on chicken meat during low-temperature storage and provided useful information for C. jejuni risk management.