Microwave-Assisted Thermal Sterilization and Pasteurization

Thermal sterilization and pasteurization are important processes in the food industry for the production of microbiologically safe foods with extended shelf life. Conventional thermal processing operations use saturated steam from coal or natural gas boilers to inactivate pathogenic and spoilage bacteria. These operations for packaged foods have severe limitations, such as lengthy processing times, low energy efficiency, poor food quality, and high carbon emissions due to the reliance on fossil fuels. Microwave-assisted thermal sterilization and pasteurization hold the potential to overcome some of those limitations. Microwave heating provides fast, volumetric, and energy-efficient heating, and can be directly powered by renewable electric sources (such as solar, wind, and hydro power). This chapter provides an overview of the principles and requirements of thermal processing, emphasizing their importance in achieving food safety and shelf stability. Furthermore, it presents recent advancements in 915 MHz single-mode microwave-assisted thermal sterilization (MATS) system and the microwave-assisted pasteurization system (MAPS), which have gained FDA acceptance and a non-objection letter from USDA FSIS. Finally, the chapter discusses the future potential of using solid-state microwave technology in improving the design of microwave heating systems.