Microwave irradiating sterilization process

Abstract

A process for sterilizing a material contained in a sealed microwave permeable package which is stored, under normal pressure, in a heat resisting and pressure resisting support during microwave irradiation. The heat resisting and pressure resisting support is conveyed on a conveyor belt into a plurality of microwave heating chambers in which local heating waveguides are provided in close proximity to the heat resisting and pressure resisting support and overall heating waveguides are provided at the wall of the microwave heating chambers. The heat resisting and pressure resisting support with the package is alternately irradiated by the local heating waveguides and the overally heating waveguides during conveyance through the microwave heating chambers so as to effect the substantially uniform heating of the material in the package. To regulate the degree to which the peripheral portions of the package are heated, the distance between the local heating waveguides and the package can be adjusted. To further facilitate the substantially uniform heating of the material in the package, the heat resisting and pressure resisting support containing the package can be inverted during conveyance.