Response surface Modeling for the inactivation of Escherichia coli O157:H7 on green peppers (Capsicum annuum) by ozone gas treatment

The effects of ozone gas concentration (2 to 8 mg/l), relative humidity (RH) (60 to 90%), and treatment time (10 to 40 min) on inactivation of E. coli O157:H7 on green peppers were studied using response surface methodology. A 3-factor Box-Behnken experimental plan was designed and microbial log reduction was measured as a response. The statistical analysis of developed predictive model suggested that ozone gas concentration, RH, and treatment time all significantly (P < 0.01) increased the rate of log reduction of E. coli O157:H7. Among the 3 factors, the effect of ozone gas concentration on bacterial Inactivation was the greatest, while the effect of RH was the least. The interaction between ozone gas concentration and RH exhibited a significant and synergistic effect (P < 0.05).