Bacterial count reduction and enzyme inactivation in bovine whole milk by pulsed electric field (PEF)
processing combined with pre-heating and intermediate cooling was compared with that induced by
thermal treatments (maximum of 63 C for 30 min and 73 C for 15 s). Milk was pre-heated to 55 C for
24 s and PEF-treated in continuous mode at electric field intensities of 15.9e26.2 kV cm1 for 17e101 ms.
PEF treatments reduced the number of inoculated (8.3 log cfu mL1) Escherichia coli and Listeria innocua
to less than 2 log cfu mL1. PEF treatments at 20.7e26.2 kV cm1 reduced the total plate count and
indigenous alkaline phosphatase activity to a level similar to that measured following thermal treatments.
Treatment at 26.1 kV cm1 for 34 ms, combined with pre-heating, reduced the activity of plasmin,
xanthine oxidase and lipolysable fat by 12%, 32% and 82%, respectively, compared with raw milk.