Radio Frequency Dielectric Heating (RFDH): A Process Lethality Treatment that Impacts Unique Functionality

Radio frequency dielectric heating (RFDH) is a microwave-type heat treatment that processors could use on sensitive dairy powders such as packaged infant formula to reduce foodborne pathogens such as Salmonella and Cronobacter sakazakii. Researchers at Kansas State University discovered that RFDH can eliminate up to 99.999% of these pathogens in the powders. The extreme processing caused a yellow color in the powder that was noticeable upon rehydration. Researchers exposed low-heat (LH) and high-heat (HH) nonfat dry milk powders to RFDH with different time-temperature combinations and measured their color, protein content and water solubility before and after each treatment. LH samples treated with RFDH had better functional properties than HH samples. </P> This study gives the dairy industry another method to improve the food safety of nonfat dry milk powders especially those used in sensitive products. Additional reports are in development that will aid the industry in determining the required process intensity that will be effective and still be acceptable in infant formula.