EFFECT OF RADIO-FREQUENCY ENERGY ON BIOLOGICAL-MEMBRANES AND MICROORGANISMS

In order to study the use of radio frequency (RF) heating to inactivat e microorganisms at mimer temperatures, its effect on model systems (l iposomes) and whole cells was evaluated. The effect of RF energy on le akage of 6-carboxyfluorescein from liposome vesicles was studied. Both influences of the applied frequency and of membrane composition were demonstrated. Radio frequency fields appeared to result in membrane da mage which could not be attributed to thermal effects Exposure of lipo somes to RF fields with frequencies of 27 and 100 MHz resulted in lysi s of the vesicles. In addition, growth of Saccharomyces cerevisiae app eared to decrease in the presence of RF fields of 27 and 100 MHz. Effe cts of RF fields on Erwinia carotovora cells at sublethal temperatures could not be demonstrated Moreover, when RF energy was applied as a h eat treatment, no additional effects were detectable. Advantages of RF heating are probably not to be found in inactivation treatments al mi lder temperatures. It is concluded that RF energy can serve as an alte rnative heating mode in terms of quick and efficient reduction of micr obial load, in specific cases. (C) 1996 Academic Press Limited.