Abstract
Many processing techniques have been developed to produce cooked rice packed under semiaseptic condition (here in after called semi-aseptic cooked rice) with less microbial spoilage, better taste and higher quality. In this study, effect of heat-resistant microorganisms in rice on commercial sterility of cooked rice was examined using pH-controlled rice. Improvement method of cooking process was investigated to upgrade the storage stability of cooked rice with microorganisms based on the concept of commercial sterility for the retort pouch foods. The growth of Bacillus subtilis isolated form brown rice was not inhibited on rice adjusted pH 4.6 and pH 5.0 at 30°C. To ensure the commercial sterility of semi-aseptic cooked rice, the isolated B. subtilis strain should be inactivated in heat cooking process. The conditions of heat cooking was investigated for semi-aseptic cooked rice adjusted pH 4.6 or pH 5.0 to ensure equivalent eating quality to conventional process and commercial sterility against B. subtilis. The optimum cooking condition for the rice of pH 4.6 was 18 minutes with 98°C and that for the rice of pH 5.0 was 14-16 minutes with 105°C or 9-11 minutes with 110°C.
