Development of a predictive model for the growth of Staphylococcus aureus in costeño chesee covered with active film

Abstract

Staphylococcus aureus is a foodborne bacterium frequently isolated from cheeses, and it is responsible for causing food poisoning. The purpose of this study was to develop a secondary model to assess the growth of S. aureus in costeño cheese packaged with an active film. Costeño cheese samples were inoculated with S. aureus and covered with an active film made from an aqueous extract of Schinopsis balansae. Subsequently, the cheese samples were stored at temperatures of 6, 12, 18, and 21 °C. The Huang model was applied to the experimental data of S. aureus to determine growth parameters. The maximum growth rate (µmax) was then used as a function of temperature to create the secondary model using a polynomial equation. The results indicate that the application of the active film of S. aureus had a significant influence on growth parameters of S. aureus such as µmax, lag-phase (λ), and maximum cell population (Ymax) in Costeño cheese. The validation process included measuring the indices: accuracy factor (Af), bias factor (Bf), and root mean square error (RMSE). The secondary model exhibited Af and Bf factors close to one, suggesting that the polynomial models are viable to predict S. aureus growth in cheese packaged with active film, considering temperature and storage time.