Effect of water activity on inactivation of Listeria monocytogenes using gaseous chlorine dioxide – A kinetic analysis

Abstract The aim of this study was to investigate the effect of water activity (aw) on inactivation of Listeria monocytogenes using gaseous chlorine dioxide (ClO2 (g)) under room temperature. Surface-inoculated tryptic soy agar (TSA) plates adjusted to 9 different water activity levels ranging from 0.994 to 0.429 were used as samples exposed to ClO2 (g) at 150, 250 and 350 ppm for different durations of treatment time. Results showed that the antimicrobial effect of ClO2 (g) significantly decreases as the aw level and ClO2 (g) concentration decrease. Nonlinear models, such as the modified Chick model and the Weibull model, were used to describe the inactivation kinetics of L. monocytogenes. The results showed that the modified Chick model, which is based on chemical reaction kinetic, was more suitable to describe the inactivation kinetics of L. monocytogenes (RMSE