Earlier this fall, PPPL and the U.S. Department of Agriculture (USDA) signed an interagency agreement to jointly develop new pasteurization methods that use radio frequency (RF) waves and microwave heating. These heating techniques -- also used to warm plasma in a fusion device -- are being tested for pasteurizing raw liquid foods such as eggs, fruit juices, and milk. "This is another example of applying our fusion and plasma science capabilities to an area that benefits the U.S. public," said PPPL Technology Transfer Head Lewis Meixler.
The $120,000 agreement between the two federally funded agencies came about after researchers at the USDA's Eastern Regional Research Center (ERRC) in Philadelphia evaluated RF radiation while exploring improved methods for pasteurization. Initial results and subsequent evaluation of micro-organisms introduced into liquid foods indicate that RF radiation is a potentially effective means for pasteurization.
RF waves offer advantages over the traditional pasteurization method of directly heating raw liquid foods. The direct method often heats foods unevenly, possibly resulting in incomplete pasteurization in lower temperature regions and in denaturing foods in overheated regions. Using radio frequency waves in the appropriate wavelength may allow pasteurization without heating liquid foods to temperatures that cause food deterioration.
The ERRC is collaborating with PPPL because of the Laboratory's extensive experience in the application of RF and microwave radiation to the study of plasmas. The Laboratory has particular expertise in optimizing the absorption of RF and microwave energy into a receiving medium. Experience includes the measuring of RF parameters, instrumentation, the design and fabrication of antennas, and the safe handling of these components.
A three-person team from PPPL, including a physicist, an engineer, and a technician, are involved in the project. The work is scheduled to begin at ERRC this fall and conclude about six months later. The PPPL team will assist the ERRC researchers in equipping their facility with the necessary RF power source, as well as providing the expertise to enable the measurement of power deposited, power launched, and launch efficiency. In addition, the PPPL group will concentrate on optimizing the RF launch configuration, and help monitor the effect of deposited power on the pasteurization process.
The agreement between ERRC and PPPL supports a memorandum of understanding between Secretary of Agriculture Dan Glickman and former Energy Secretary Hazel O'Leary to use one federal agency's technologies to benefit research at other federal agencies.