Microbial inactivation models of Salmonella Typhimurium in radio frequency treated eggs

Salmonella Typhimurium 53647 was inactivated with selected radio frequency processes in in-shell eggs. The combination of hot air (HA), hot water immersion (HW), and hot water spray (HWS) were evaluated alone (56.7 degrees C) and in combination with radio frequency (40.68 MHz, 35 W, 4.5 min). Microbial inactivation did not follow first-order kinetics in any treatments. Alternative mathematical approaches were used to describe the inactivation of S. Typhimurium in in-shell eggs. These models were based on the Weibull distribution, the logistic distribution, a model for extreme tailing, and a model for flat shoulder with log-linear continuation. The goodness of fit evaluated with several statistical parameters (R-2, RSME, A(f), B-f, AIC) showed the Weibull distribution as the best model to describe the microbial inactivation during radio frequency treatments, followed by the extreme tailing model. The information from the present study is currently used for process optimization of the radio frequency equipment. In addition, it provides an important tool to predict and validate the response of Salmonella inoculated in fresh eggs under specific radio frequency pasteurization conditions.

Automated summary

Salmonella Typhimurium inactivation in in-shell eggs was studied using radio frequency processes combined with hot air, hot water immersion, and hot water spray. The inactivation of Salmonella did not follow first-order kinetics. Statistical analysis indicated that the Weibull distribution and extreme tailing model were the best models to describe the microbial inactivation during radio frequency treatments.