Abstract: This work was undertaken to establish a model describing the inactivation of Weissella viridescens on lowtemperature smoked ham with ultra-high pressure thermal sterilization (HPTS). Weissella viridescens suspended in phosphate buffered saline and smoked ham inoculated with 108–109 CFU/mL of this strain were subjected to moderate heating (40, 45 and 50 ℃) combined with high pressure (200–500 MPa) held for 5, 10, 15, 20, 25, 30 min. The number of surviving cells was counted by the thin agar layer method. Inactivation curves describing the logarithmic value of the number of inactivated cells as a function of time were fitted with a first-order linear model and the Weibull and Logistic nonlinear models. The goodness of fit of the fitted models was examined by the correlation coefficient (R2), accuracy factor (Af) and mean square error (MSE). It was found that the inactivation of Weissella viridescens in situ was slower than in vitro after HPTS, which was due to the presence of macromolecular substances in the ham matrix including protein and fat, protecting bacteria from damage. Finally, the Logistic equation was the best model to describe bacterial inactivation in vitro and in situ, and could provide the theoretical foundation to predict Weissella viridescens inactivation on smoked hams.

Key words: ultra-high pressure, Weissella viridescens, smoked ham, in vitro, Logistic model