Strategy for reduction of microorganisms during rice cakes manufacturing process

Abstract

This study was conducted to establish effective reduction strategy during the manufacturing process of rice cakes. Simple washing (3 times) and ultrasonic washing (40 kHz, 10 min) were used in the rice washing process, and sodium hypochlorite (100 ppm, 5 min) and chlorine dioxide (20 ppm, 5 min) were used as chemical disinfectants. Combination treatment using ultrasonic washing and the two chemical disinfectants was also performed. The chemical disinfectants were more effective than the ultrasonic cleaning in a single treatment of each method, and sodium hypochlorite showed a greater reduction effect than chlorine dioxide. The combination treatment using both chemical disinfectant and ultrasonic cleaning was found to be more effective than using a single treatment, and no significant difference was observed in the results based on the disinfectant used. During the heating process, which is an important control point of HACCP system, total aerobic bacteria, coliforms, Bacillus cereus and Escherichia coli were inactivated. UV sterilization (30 min, 60 min) was applied as the nonthermal treatment and compared with the general drying method (5, 12 h) during the cooling process of rice cakes. No bacteria were not found after the treatment, whereas the total number of bacteria in the naturally dried rice cakes increased after 12 h, indicating the potential of UV sterilization as an important control point during the cooling process of rice cakes.