Pasteurization of milk using pulsed electrical field and antimicrobials

The inactivation of naturally occurring microorganisms in raw skim milk by pulsed electric field (PEF) treatment alone and combined with the antimicrobial agents nisin and lysozyme, added both singly and together, was investigated. A 7.0-log reduction of microorganisms found in raw skim milk was achieved through a combination of PEF treatment (80 kV/cm, 50 pulses), mild heat (52 degreesC), and the addition of both the natural antimicrobials nisin (38 IU/mL) and lysozyme (1638 IU/mL). The combination of PEF, mild heat, and antimicrobials resulted in a much higher microbial inactivation than the sum of the individual reductions achieved from each treatment alone, indicating synergy. Varying the pH from 6.7 to 5.0 had no effect on microbial inactivation.