Microwave sterilization is a thermal process [1]. It delivers energy to the food package under pressure and
controlled temperature to achieve inactivation of bacteria harmful for humans.
Most processed foods today are heat treated to kill bacteria. Prolong exposure to high heat often diminishes
product quality. Microwaves interact with polar water molecules and charged ions. The friction resulting from
molecules aligning in rapidly alternating electromagnetic field generates the heat within food. Since the heat is
produced directly in the food, the thermal processing time is sharply reduced. The color, texture and other
sensory attributes of foods processed by microwave sterilization are often better compared with those of
conventionally retorted foods while meeting microbial safety requirements. Currently, researchers are
generating scientific and engineering information to support regulatory acceptance of microwave sterilization
technology for industrial applications.
US Federal Communication Commission (FCC) allocates 915 MHz and 2450 MHz bands for industrial and
domestic microwave heating applications. The microwave sterilization technology developed at Washington
State University uses the combination of 915 MHz microwave and conventional heating to improve heating
uniformity.