The 915 MHz microwave-assisted pasteurization process improves thermal pasteurization, by heating a product to 194 F/90 C, which is below the boiling point of water and reduces the numbers of pathogenic bacteria a million times over.
It is seen as an alternative to commercial canning (sterilization) processes for shelf-stable foods and in trials it saw better results in mollusks, shrimp and tofu.
American Frozen Food Institute
Juming Tang, professor, WSU, told FoodQualityNews.com it came up with the idea for the project after speaking to committee members at the American Frozen Food Institute.
It also extends from another technology developed at the university lab called MATS (Microwave Assisted Thermal Sterilization).
“The system is designed in such a way, it is adaptable to small, mid-sized and large companies that are concerned about food safety of pre-packaged chilled meals,” said Tang.
“Our intent is commercialize the technology and we are opening up our facilities for food companies to develop food meals and concepts for expanded markets.”
The research is funded by a $5m US Department of Agriculture (USDA) National Institute of Food and Agriculture (NIFA) grant awarded in 2011 to WSU and partners across the country.
Traditional canning operates at 249 F/120 C or higher to kill the pathogen Clostridium botulinum; but the temperature, pressure and length of the canning process often degrades food quality, making it less acceptable to consumers, said Tang.
“The microwave-assisted pasteurization system can semi-continuously process 8- to 20-oz. pre-packaged chilled meals and supports the mandate of the federal 2011 Food Safety Modernization Act, which demands food producers add steps in food production operations to make sure products are safe,” he added.
WSU can work with food companies to adapt the technology to a producer’s needs and then manufacture production equipment via a third party, making the system 'scalable for industrial production,' said Tang.
Shrimp and tofu
WSU anticipates licensing this technology to its start-up, Food Chain Safety, for commercialization in the coming months.
The process also allows traditionally frozen meals to be refrigerated instead of frozen.
Barbara Rasco, professor, School of Food Science and collaborator on the project, WSU said the trial had some ‘exciting early results’.
“The quality of microwave pasteurized foods – specifically mollusks, shrimp and tofu – is substantially better than conventionally pasteurized foods,” she said.
“A shelf life exceeding one month at refrigeration temperatures has been achieved for several formulated food items, including stroganoffs, curries, burritos and hors d’oeuvres.”
Other institutions involved with the project include the University of Tennessee, North Carolina State University, the US Army Soldier Systems Center and USDA-Agricultural Research Service Eastern Regional Research Center.