Inactivation of Bacillus cereus and Salmonella enterica serovar typhimurium by Aqueous Ozone: Modeling and UV-Vis Spectroscopic Analysis

Abstract

ABSTRACTAntibacterial efficacy of aqueous ozone (O3) against B. cereus vegetative cells and S. typhimurium by was studied by using GInaFiT tool and results were validated using UV-Vis spectroscopy. Ozone gas was generated using a domestic ozone generator. Buffer solutions containing known amounts (≈108–109 cfu/mL) of bacterial pathogens were treated with aqueous ozone (200 mg/hr or 0.1 mg/l) for 16 min with sampling at 0-, 0.5-, 1-, 2-, 4-, 8- and 16-min intervals. A reduction of 4.6 log of B. cereus and 7.7 log cycle reduction of S. typhimurium was obtained in 16 min. Biphasic shoulder and double Weibull models were good fit for the experimental inactivation kinetics data. Principal Component Analysis showed discrete grouping based on the time of treatment. The highest correct classification results for SIMCA were achieved for both B. cereus and S. typhimurium after 1 and 8 min of treatment, respectively. In partial least squares regression analysis, maximum R2 values for calibration and validation were found to be 0.84, 0.80 for B. cereus and 0.90, 0.89 for S. typhimurium, respectively.