3.1 UV Treatment Decreases Microbial Counts in the Black Jasmine Rice Pericarp Beverage.
Reductions of microbial contaminants in the black jasmine rice pericarp beverage after UV treatment at 4 different conditions were shown in Fig. 1. Values were in a range of -0.10 to -0.75 log CFU/mL, which was lower than previous studies [12, 15, 20]. It is possibly due to the lower dosage used in this study since a germicidal effect of UV is dose and time dependent. Mesophilic bacteria after UV treatment was lowered in a range of -0.20 to -0.62 log CFU/mL and UV treatment at a flow rate of 0.4 L/min showed the maximum reduction, although this condition did not result in a significant number (p>0.05) when compared to a control beverage. Meanwhile, decrease in yeast and mold after UV treatment was found in a range of -0.10 to -0.75 log CFU/mL. Yeast and mold present in the black jasmine rice pericarp beverage were also insignificantly (p>0.05) decreased after UV treatment at a flow rate of 0.4 L/min. Since microbial contaminants remained in the beverage treated at this condition were 4.51 log CFU/mL for mesophilic bacteria and 2.06 log CFU/mL for yeast and mold, multiple times of UV radiation are recommended for the effective disinfection of the black jasmine rice pericarp beverage.