Inactivation of S. cerevisiae and E. coli by pulsed electric fields: the effect of flow conditions on treatment efficiency

In this work, microbial inactivation of E. coli and S. cerevisiae cells inoculated in a model solution has been studied using a continuous flow PEF system. The influence of flow parameters on the lethal effect and the energy efficiency of PEF treatment has been investigated in a wide range of values. Results showed that, at a fixed field strength, higher degrees of stirring of the microbial suspension achieved by increasing the flow rate with a single pass operation through the PEF chamber, or by re-circulate mode at a constant flow rate, provided a significantly increase of the effectiveness and energy efficiency of the pulse treatment. Finally, results of this study highlight that improving of the PEF sterilization efficiency need of a new approach where not only electric and microbial parameters but also flow parameters should be simultaneously involved