Inactivation kinetics of slightly acidic electrolyzed water combined with benzalkonium chloride and mild heat treatment on vegetative cells, spores, and biofilms of Bacillus cereus.

Bacillus cereus can exist as vegetative cells, spores, and biofilms in food-processing environment, posing a big challenge for the food industry. The objective of this study was to examine the inactivation efficacy of slightly acidic electrolyzed water (SAEW) in combination with benzalkonium chloride (BAC) and mild heat treatment (50 and 60 °C) on B. cereus strains (ATCC 10987 and ATCC 14579). The inactivation efficacy of SAEW was found to be largely dependent on available chlorine concentration (ACC) level and exposure time as well as B. cereus strains and growth conditions. SAEW with ACC of 40 ppm reduced ATCC 10987 and ATCC 14579 vegetative cells to the non-detection limit within 30 s. and 1 min, respectively. Combination treatment with SAEW+60 °C for 10 min resulted in reductions of ATCC 10987 spores, ATCC 14579 spores, and ATCC 10987 biofilms at 0.76 logCFU/ml, 0.59 logCFU/ml, and 1.28 logCFU/cm, respectively. While, treatment with SAEW+BAC + 60 °C for 10 min resulted in reductions of ATCC 10987 spores, ATCC 14579 spores, and ATCC 10987 biofilms at 1.91 logCFU/ml, 1.98 logCFU/ml, and 2.62 logCFU/cm, respectively. The inactivation kinetics under different ACC of SAEW and in combination with BAC and mild treatment were determined by Weibull model. The calculated adjusted correlation coefficients (R) and root mean sum of squared error (RMSE) values for all curves were found to be ranges from 0.95-0.99 and 0.04-0.23, respectively, indicating that the Weibull model precisely predicted the inactivation kinetics of B. cereus during SAEW in combination with BAC and mild heat treatments. These results suggest that SAEW in combination with BAC and mild heat may be used as an effective cleaning strategy against B. cereus in the food contact surfaces.