Development of Predictive Models for the Growth Kinetics of Listeria monocytogenes on Fresh Pork under Different Storage Temperatures

Abstract

This study was conducted to develop a predictive model to estimate the growth of Listeria monocytogenes on fresh pork during storage at constant temperatures (5, 10, 15, 20, 25, 30, and 35°C). The Baranyi model was fitted to growth data (log CFU per gram) to calculate the specific growth rate (SGR) and lag time (LT) with a high coefficient of determination (R(2) > 0.98). As expected, SGR increased with a decline in LT with rising temperatures in all samples. Secondary models were then developed to describe the variation of SGR and LT as a function of temperature. Subsequently, the developed models were validated with additional independent growth data collected at 7, 17, 27, and 37°C and from published reports using proportion of relative errors and proportion of standard error of prediction. The proportion of relative errors of the SGR and LT models developed herein were 0.79 and 0.18, respectively. In addition, the standard error of prediction values of the SGR and LT of L. monocytogenes ranged from 25.7 to 33.1% and from 44.92 to 58.44%, respectively. These results suggest that the model developed in this study was capable of predicting the growth of L. monocytogenes under various isothermal conditions.

Predictive Growth Modeling of Listeria monocytogenes in Rice Balls and Its Risk Assessment

“…Particularly, tuna or ham rice balls mixed with mayonnaise exhibited the lowest T min (−9.43°C and −15.40°C, respectively) followed by those mixed with soy sauce and gochujang. T min of L. monocytogenes in rice balls is much lower than other reports [34][35][36][37]. T min of L. monocytogenes grown in culture media under optimal conditions was reported from 0.5°C to 5°C [38].…”

“…In the Baranyi model, which was the most accurate among the three primary models, R 2 for SGR and LT model equations was >0.95, indicating good fit. Various developed models have been shown to be capable of predicting the growth of L. monocytogenes under the certain conditions [34]. T min is the minimum temperature that facilitates bacterial growth estimated by the traditional Ratkowsky square model; in this study, we identified slight differences in T min between tuna and ham rice balls, with ham rice balls exhibiting a lower value than tuna rice balls.…”