APPLICATION OF A LOG-LOGISTIC MODEL TO DESCRIBE THE SURVIVAL OF YERSINIA-ENTEROCOLITICA AT SUBOPTIMAL PH AND TEMPERATURE

A log-logistic model previously used to describe the thermal inactivat ion of microorganisms has been applied to predict accurately the survi val of Yersinia enterocolitica under conditions of sub-optimal tempera tures (0-23-degrees-C) and growth inhibitory pH values for a number of different acidulants. Predictions from the model were also compared t o observed survival times of Y. enterocolitica in mayonnaise and were found to be in excellent agreement. However in yoghurt the model overe stimated survival of this organism at both 20 and 4-degrees-C but woul d 'fail safe' if used for predictive purposes. The discrepancy in yogh urt is discussed.