Inactivation of <i>E. coli</i> 8739 in Enriched Soymilk Using Pulsed Electric Fields

Abstract

ABSTRACT: Soymilk enriched with dairy proteins was subjected to pulsed electric fields (PEF) to evaluate the inactivation of Escherichia coli 8739 and the extension of microbial shelf‐life. The maximum thermal exposure level of sample was 60 °C for 1.6 s during a PEF treatment. A 5.7‐log reduction was achieved using PEF at 41.1 kV/cm for 54 μs. PEF inactivation of E. coli 8739 followed a 1st‐order kinetic model. D‐values of E. coli 8739 were 31.9,18.6, and 11.0 μs at 30,35, and 40 kV/cm, respectively. PEF treatment at 41.1 kV/cm for 54 μs significantly extended the microbial shelf‐life at 4 °C ( P &lt; 0.05). No significant change in brightness and viscosity of PEF‐treated samples was observed during a 30‐d storage at 4 °C. PEF was found effective in inactivation of E. coli in and extension of microbial shelf‐life of enriched soymilk.