Effect of induced electric field on microorganism inactivation, nutrients and physicochemical properties of milk

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.