Rice can be the contaminating with soil-borne bacteria. Furthermore, the contaminated bacteria can be grown during immersion process for produce wet-milled rice flour. Therefore, disinfectants can be added during the immersion process. Antibacterial activities of the natural disinfectant, fermented rice spent water (FRSW), and the chemical disinfectants, chlorine dioxide (CD) and sodium benzoate (SB), were respectively determined when added in pure cultures of target bacteria such as Salmonella typhimurium, Escherichia coli, and Bacillus cereus or when added to immersion water in the immersion process. In addition, rinsing effects for removing bacteria were determined when rice was rinsed with water before and after the immersion process. Antibacterial activities were rapidly increased as increasing amounts of the disinfectants are added to the pure cultures of the target bacteria. Antibacterial activity of CD was the most effective among the three tested disinfectants when added to the pure cultures of the target bacteria, respectively. Those of the same disinfectants were increased when they were increasingly added to the immersion water. However those of the disinfectants were less effective when added to the immersion water. On the other hand, rinsing effects for removing bacteria were the most effective when rice was rinsed only with water without the immersion process. Collectively, rinsing rice with water only was more effective than using disinfectants in the immersion water during rice flour production.

Steamed rice is usually used as an essential ingredient when Takju or Yakju is brewed in Korea. Alternatively, non-steamed rice can be used to keep thermolabile nutrients and fresh tastes richer in Takju or Yakju. In this study, therefore, the physicochemical properties (ethanol and sugar contents, pH, total acidities, and turbidities)and the fermentative microbial profiles (aerobic mesophillic bacteria (AMB), fungi, lactic acid bacteria (LAB), acetic acid bacteria (AAB), and Escherichia coli and coliforms) have been compared among 4 Takju and 1 Yakju samples brewed using steamed or non-steamed rice. Yakju brewed using non-steamed rice has approximately 2-3 times higher ethanol and sugar contents than other 4 Takjus brewed using steamed or non-steamed rice. The pH and total acidity values of all the 5 samples ranged 3.77-4.30 and 0.12-0.35, respectively. As for turbidities, Yakju brewed using nonsteamed rice was transparent, but other 4 Takjus were not. The AMB and fungal counts for Yakju brewed using nonsteamed rice were approximately 104-fold less than those for 4 Takjus. The LAB counts for Takju and Yakju brewed using non-steamed rice were 103-fold less than those for Takjus brewed using steamed rice. The AAB counts ranged 2-6 log10CFU/mL for all the 5 samples. E.coli and coliforms were not detected. Overall, there was no significant difference in microbial counts among 4 Takjus brewed using steamed or non-steamed rice, but Takju has higher microbial counts than Yakju. All the 5 samples were conclusively considered to be hygienically brewed and processed containing plenty of beneficial microorganisms.