Acetic, Lactic, and Hydrochloric Acid Effects on Staphylococcus aureus 196E Growth Based on a Predictive Model

Mathematical models were developed with a modified Gompertz function to predict Staphylococcus aureus 196E growth, where pH was altered with either acetic, lactic or hydrochloric acid. S. aureus 196E was inoculated into broth formulated with 0.5, 4.5 or 8.5% sodium chloride, adjusted to pH 5.0, 6.0 or 7.0, and incubated aerobically at 12, 20 or 28°C. Each model adequately predicted log growth, and some interactive relationships between independent variables upon population growth were significant (p<0.05). Predictions of growth showed that acetic was generally more inhibitory than lactic or hydrochloric acids.