Modeling the inactivation of E. coli O157:H7 (ATCC 43888) in high hydrostatic pressure treated tomato juice

High Hydrostatic Pressure (HHP) is a non-thermal preservation method that enhances microbial safety while maintaining nutritional and sensory attributes. In this study, the inactivation of Escherichia coli O157:H7 in tomato juice was quantified using the Geeraerd primary model, fitted within a Bayesian framework for all pressure-time combinations. Models that would be expected to perform best were pooled and trialed from the primary fits using a regression model. A global (primary-secondary) quadratic secondary model was then applied to describe the dependence of log₁₀k_max and residual colonies (N_Res) on pressure, incorporating random effects for each pressure level. Results showed a monotonic increase of k_max with pressure, with the strongest inactivation observed at 450 MPa, while residual populations declined consistently across the pressure domain. Posterior predictive checks confirmed that the Full Geeraerd model provided an accurate description of inactivation kinetics, and that the quadratic secondary structure adequately captured pressure dependence. These findings demonstrate that HHP substantially accelerates microbial inactivation, and that a two-stage Bayesian modeling framework combining primary and secondary models can provide robust predictions to support the optimization of non-thermal food preservation processes.