Submitted to: Journal of Food Protection
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/24/2003
Publication Date: 1/3/2004
Citation: Yoon, K.S., Burnette, C.N., Oscar, T.P. 2004. Development of predictive models for the survival of campylobacter jejuni on cooked chicken breast patties and in broth as a function of temperature. Journal of Food Protection. 67(1):64-70. Interpretive Summary: Campylobacter jejuni causes more cases of illness per year than any other pathogen of food origin including Salmonella. Poultry meat is a major source of C. jejuni in humans. It is reported that 64% of turkeys and 89% of chickens in the U.S. carry this pathogen. Fortunately, C. jejuni is sensitive to oxygen and thus, levels of this pathogen decline on poultry meat after processing. Mathematical models that predict the rate of death, as a function storage conditions such as time and temperature are valuable tools for helping food technologists assess the risk of illness from pathogens of food origin. In the current study, a mathematical model was developed that predicts the decline in C. jejuni on chicken as a function of temperature. An interesting finding in the study was that C. jejuni death was more rapid at room temperatures than at refrigerated temperatures.
Technical Abstract: The objective of this study was to model the kinetics of Campylobacter jejuni survival on cooked chicken breast patties and in broth as a function of temperature. Both patties and broths were inoculated with 106 stationary phase cells of a single strain of C. jejuni (ATCC 43051) and incubated at constant temperatures from 4 C to 30 C in 2 C increments under aerobic conditions. In most cases, a three phase linear model fit the primary survival curves well (r2 = 0.97 to 0.99) at all incubation temperatures, regardless of model medium, indicating the presence of a resistant subpopulation of C. jejuni that would not be eliminated without thermal processing. Secondary models that predicted lag time (LT) and specific death rate (SDR) as a function of temperature were also developed. The Davey and Boltzmann models were identified as appropriate secondary models for LT and SDR, respectively, based on goodness-of-fit (Boltzmann, r2 = 0.96, Davey, r2 = 0.93) and prediction bias and accuracy factor tests. Results indicated that C. jejuni can survive well at both refrigeration and ambient temperatures, regardless of model medium. Reduced survival of C. jejuni characterized by shorter lag time and faster death rates was observed both on patties and in broth at ambient temperatures. In addition, the average, maximum log reduction of C. jejuni at 4 C to 30 C was 1.5 log, regardless of storage temperature or model medium. These findings suggest that C. jejuni found on contaminated poultry products has the potential for remarkable survival under conditions non-permissive to growth and thus, could cause foodborne illness, if the poultry is not sufficiently cooked.