Basic Study for High Temperature and Short Time Sterilization by Continuous Microwave Heating for Solid Foods or High Viscous Foods

Abstract

This report of basic study will discuss a technique of heating solid foods or high viscous foods in transit on a conveyor for possible commercial applications. By using model solutions with adjusted ingredients, we have found that: 1) Continuous radiation against the model solutions in transit from plural units of microwave generators with different heating characteristics at a relatively short irradiation distance of 45mm causes dispersion of edge effects and is effective for uniform temperature within the solutions. 2) Scanning a top surface of the model solutions by wave guides is effective for uniform temperature within the solutions as they are exposed to electric fields of relatively high intensity. 3) With a distilled water immersing method, a 2mm thick water jacket is an optimum condition for minimizing the edge effects. This indicates that use of the distilled water immersing method is effective in continuous high temperature short time sterilization of foods that call for highly accurate thermal control. On the basis of these results, we will plan designing a system of continuous sterilization of solid foods at temperature of 100 degrees Celsius and over, and continue basic studying behavior of microwaves and microwave sterilization with various solid foods.