Microwave Sterilization

January 15/Science Letter -- According to reports from North Carolina State University, "The feasibility of peanut beverage sterilization by continuous microwave heating as an alternative to conventional ultrahigh temperature (UHT) system processing was studied. Dielectric properties of two products, Peanut Punch (Nestle Trinidad and Tobago Ltd., Port of Spain, Trinidad and Tobago) and Jamaican Irish Moss Peanut Drink (distributed by Eve Sales Co., Bronx, NY) were measured.

"The products had similar dielectric properties. Values for the dielectric constant (average of 60) and dielectric loss (average of 23) indicated that the two products were good candidates for rapid microwave heating. The products were processed in a 5kW focused microwave unit, at two different flow rates, 1 and 2L/min. The short time required to reach 130C and the uniformity of the temperature distribution indicated that microwave heating could be used as a sterilization step in a UHT process for peanut-based beverages," wrote C.M. Sabliov and colleagues, North Carolina State University, Department of Agriculture.

The researchers concluded, "Further studies need to be conducted on microbiological and chemical changes of the product before continuous microwave heating can be implemented as an alternative sterilization step to conventional UHT processes of peanut beverages."

Sabliov and colleagues published their study in the Journal of Food Processing and Preservation ("CONTINUOUS MICROWAVE PROCESSING OF PEANUT BEVERAGES." Journal of Food Processing and Preservation, 2008;32(6):935-945).

For additional information, contact T.H. Sanders, North Carolina State University, Dept. of Agriculture, ARS, Market Qual & Handling Research Unit, Dept. of Food Science, Box 7624, Raleigh, NC 27695, USA.

From the January 19, 2009, Prepared Foods E-dition