Kinetic Modeling of Microbial Inactivation in Juices Treated With Pulsed Electric Fields (PEF): A Comparative Study on Microbial Heterogeneity and Food Matrix Effects.

Pulsed electric field (PEF) processing is a promising technology for preserving fruit and vegetable juices. This research study evaluated the effect of pulsed electric fields (PEF) at 20 kV/cm on the microbial and quality parameters of pomegranate, tomato, and carrot juices. The inactivation kinetics of Escherichia coli strains (K12 and FAM 21843) and Saccharomyces cerevisiae strains (AD1890 and 130.0014) were fitted using a global model, which combined a log-linear primary model with a second-order polynomial. for describing the polyphasic inactivation kinetics. Maximum microbial inactivation rates (k max ) increased with the increase of Wτ, reaching > 5-log reductions for E. coli strains in pomegranate and carrot juice, and > 3.85-log reduction in tomato juice. Among strains, S. cerevisiae 130.0014 showed the highest k max values above > 80 kJ/kg in pomegranate and tomato juices. Minor differences were observed at high Wτ levels among E. coli strains in pomegranate juice and among S. cerevisiae strains across all the food matrices. Furthermore, the occurrence of sublethal injury was low to E. coli strains under PEF, independent of the food matrix, within pomegranate juice, showing the highest levels. Quality analysis of all juices revealed that PEF did not affect antioxidant compounds or their antioxidant activities, as no statistically significant values (p < 0.05) were identified. Overall, the effectiveness of PEF in microbial inactivation is primarily governed by Wτ, with some food-matrix-dependent variations. These findings highlight PEF's potential as a food processing alternative that preserves quality while achieving microbial inactivation.