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A continuant-flow induced electric field (IEF) apparatus was presented for the treatment of the milk. The electric field originated from the magnetic energy, and the volumetric heating of the milk was observed. The inactivation effect of IEF treatment on the milk inoculated with exogenous bacteria was investigated under different IEF strengths (11.11, 14.81 and 18.52 V/cm) and the duration (98, 131 and 196 s), IEF treatment reduced E. coli and S. aureus by more than 5.9 Log CFU/mL, and the damage to cell membrane caused by the non-thermal effects was observed via SEM images. Under 14.81 V/cm for 196 s, the total number of colonies in raw milk was reduced by 4.58 Log CFU/mL. The results demonstrated IEF treatment effectively preserved nutritional properties of milk, with no significant influence on protein content. Furthermore, IEF-treated milk exhibited smaller color changes, compared to conventional heat (CH) treatments, while the process did not lead to the accumulation of casein and milk fat globules. Because of rapid temperature rise and electroporation effect on microorganisms, it suggests that IEF treatment has the potential to dairy processing. • The volumetric heating of the milk was observed via induced electric field. • IEF treatment reduced E. coli and Staphylococcus aureus by more than 5.9 Log. • IEF treatment had minimal effect on physicochemical properties of the milk. • Significant cytoarchitectural damage was observed by SEM. [ABSTRACT FROM AUTHOR]

Non-conventional heating technology based on electric fields can be utilized to process liquid foods. In this study, the induced electric field (IEF) was investigated to clarify its inactivation mechanism on E.coli. Staining results show that inactivation of E.coli by IEF can be attributed to the reversible destruction of the cell membrane, followed by the denaturation of intracellular enzymes, and finally the irreversible rupture of the cell membrane. The increased levels of extracellular proteins and nucleic acids were also observed. IEF treatment at 400 Hz and 800 V (or 53 V/cm) results in a reduction of 4.5 log CFU·mL−1 in the number of E.coli. Storage life analysis shows that IEF treatment can improve the stability of apple juice and the content of bioactive components. Thus, IEF is a potential technique for liquid food processing. • The inactivation mechanism of induced electric field on E.coli was investigated. • A reduction of 4.5 log CFU·mL−1 of E.coli was realized by applying the IEF. • IEF treatment retains bio-active components in fresh apple juice. • The storage stability of apple juice was improved through IEF treatment. [ABSTRACT FROM AUTHOR]