Application of competitive models in predicting the simultaneous growth of Staphylococcus aureus and lactic acid bacteria in milk

The simultaneous growth of Staphylococcus aureus and lactic acid bacteria (LAB) starter culture was studied in milk at different temperatures and LAB inoculums (ranging from 12 °C to 30 °C and 103-107 CFU ml−1, respectively). The modelling and predictive ability of three competition models were evaluated. Competition coefficients representing mutual population influence were incorporated into two of the models. This enabled the use of model parameters from individual S. aureus and LAB growth curves as well as those from co-culture growth in milk. Both the results and their statistical indices showed that incorporation of averaged competition coefficients resulting from individual co-culture trials improved the prediction of S. aureus behaviour in co-culture with LAB.