Effect of different sanitizers on the microbiological quality and sensory acceptance of sanitized cooked rice

Abstract

Bacillus cereus is one of the major causes of food poisoning bacteria involved in rice and rice-based foods. It causes vomiting-type of food poisoning when more than 10 5 CFU/g presented in food. Three food-grade sanitizers were studied for their effectiveness to reduce B. cereus and total mesophilic bacteria without affecting sensory acceptance of sanitized cooked rice at the same time. The sanitizers used in the study were chlorine, citric acid and chlorine dioxide.. The effective concentration of chlorine, citric acid and chlorine dioxide in reducing Bacillus cereus and total mesophilic bacteria were 250 ppm, 0.5% and 1.0 mg/L, respectively. Inoculation of pathogenic B. cereus UBCC026 strain isolated from contaminated food into cooked rice was done to determine the effect of sanitizers on reducing total mesophilic bacteria and B. cereus. Treatment of 0.5% citric acid and 1.0 mg/L chlorine dioxide were suitable for rice sanitization because these treatments did not cause any changes of sensory characteristic of cooked rice. However, chlorine at concentration of 250 ppm was not a suitable sanitizer for rice since it showed significant (p < 0.05) differences in sensory attributes from control. Chlorine dioxide at concentration of 1.0 mg/L reduced at least 2.34 log10 CFU/g of total mesophilic bacteria and 2.64 log10 CFU/g of B. cereus. It was found that the most suitable sanitizer for rice sanitization was 1. 0 mg/L chlorine dioxide because it is the most effective in reducing total mesophilic bacteria and B. cereus compared to other two sanitizers without affecting sensory acceptance of the cooked rice.