Comparison of Inactivation Effect of Slightly Acidic Electrolyzed Water and Sodium Hypochlorite on Bacillus cereus Spores

Abstract

Bacillus cereus spores are concerns for food spoilage and foodborne disease in food industry due to their high resistance to heat and various disinfectants. The aim of this study was to investigate the inactivation of B. cereus spores by slightly acidic electrolyzed water (SAEW) in comparison to sodium hypochlorite (NaClO) with same available chlorine content (ACC). In this study, the efficacy of SAEW with different concentrations of ACC (40, 60, 80, 100, and 120 mg/L) on the inactivation of B. cereus spores, and the effect of SAEW combined with mild heat treatment (60°C), was examined in pure culture suspensions. Heat resistance and pyridine-2,6-dicarboxylic acid (DPA) release of the spores were also determined. The results showed that the sporicidal effect of the SAEW was significantly higher compared with the NaClO with the same concentration of ACC. Furthermore, the inactivation efficacy was largely dependent on ACC and treatment time. Moreover, the sporicidal activity of the SAEW was significantly improved when combined with a mild heat treatment (60°C). The majority of the DPA was released from spores, and the spores exhibited less resistance to heat after SAEW treatment for 30 min. These findings indicate that SAEW could effectively inactivate B. cereus spores, making it a promising and environmentally friendly decontamination technology for application in the food industry.

Keywords: Bacillus cereus spores; inactivation; slightly acidic electrolyzed water; sodium hypochlorite.