Optimization of co-linear-type pulsed electric field treatment chamber for milk pasteurization

Pulsed electric fields (PEFs) are increasingly employed industrially as pasteurization methods for liquid foods. However, some issues regarding heat-sensitive, high-protein liquid foods remain unresolved. The efficacy of PEFs during continuous processing depends on the structural characteristics of the processing chamber. This study presents the optimal structure of our originally developed colinear-type PEF treatment chamber, determined through a combination of experimental and numerical calculations. Our pasteurization system, with a flow rate of 10 L/h, involved an optimized PEF treatment and a moderate heat treatment at 60 °C. Our system inactivates Listeria innocua in sterilized milk by more than seven orders of magnitude. In a durability test, the system was successfully operated continuously for more than 1 h under pasteurized conditions without any damage or component adhesion on the stainless-steel electrodes. This study provides guidelines for the high-flow pasteurization of high-protein liquid foods.