Growth limits of Staphylococcus aureus as a function of temperature, acetic acid, NaCl concentration, and inoculum level

Staphylococcus aureus is one of the most prevalent causes of gastroenteritis worldwide. Knowing the precise boundary for the growth/no growth interface of S. aureus and also determining the period of time needed for bacterial growth initiation is necessary for food safety risk assessment. This study was designed to examine the combined effects of temperature, acetic acid, inoculum level and NaCl concentration on the growth of S. aureus in brain heart infusion broth. Growth was monitored by visible turbidity over a 20 days period. Statistical analysis of data showed significant effects for selected parameters on growth of S. aureus. Stepwise multiple regression was used to predict the growth initiation (R2 = 0.91, P<0.0001). To obtain a boundary model, logistic regression was used. The models accurately predicted the growth initiation and inhibition of S. aureus.