Abstract
Using a 2 kW, 27.12 MHz RF heater, studies were conducted to evaluate the effectiveness of RF heating in inactivating surrogates of both
Listeria and Escherichia coli cells in milk under continuous flow conditions. Depending on product residence time and RF power level, RF
heating was found to be capable of inactivating both Listeria and E. coli in milk, with E. coli being the more heat sensitive of the two. For a
total residence time of 55.5 s (i.e., 29.5 and 26 s in the applicator and holding tube, respectively), up to 5- and 7-log reductions were found for
heating Listeria and E. coli, respectively at 1200 W, and an applicator tube exit temperature of approximately 65 -C. This study demonstrates
that RF heating could be used to effectively pasteurize milk by manipulating incident power levels and flow rate. While these studies have
been conducted under mild fluid flow (laminar) conditions, further studies are necessary to justify its industrial application using more
realistic flow conditions.