Study on the effect of the sterilization treatments on the growth of residual Staphylococcus aureus during food processing

The influence of the sterilization treatments on the growth of residual Staphylococcus aureus CMCC (B) 26003 during food processing were discussed.Exponential phase inoculums were treated with heating, frozen, ultraviolet (UV) rays, NaClO solution and ozone water respectively, then the cells were shaken and incubated at 37℃for 12～14h.Bacterial growth was monitored by total viable count at regular time, and growth model were described by Baranyi Model.The sterilization treatments effect on the growth of residual Staphylococcus aureus was clarified by the change of the lag time (t-lag) and the maximum specific growth rate (μmax) .The results were as following:the lag time of Staphylococcus aureus treated with heating at 60℃ for 5min or NaClO 30mg/kg for 10min had significant difference with control (p<0.01) , which were 3.95h and 2.62h respectively, 2.6 and 2.0 times that of control.The maximum specific growth rate of Staphylococcus aureus treated with heating at 60℃for 5min and UV rays for 15min had significant difference with control (p<0.01) , which were 1.81lg cfu/mL.h～ (-1) and 1.83lg cfu/mL.h～ (-1) respectively, 1.1 times that of control.Growth kinetic parameter treated with 0.5mg/kg ozone water for 10min and-18℃for 3 days had no significant difference with control.