Modeling The Growth Dynamics of Staphylococcus Aureus In Moroccan Jben Soft Cheese Under Different Storage Temperatures
Citation (APA 7)
Zanzan, M., Ezzaky, Y., Elidrissi, A., Boussif, K., Cadavez, V., Gonzales-Barron, U., & Achemchem, F. (2024). Modeling The Growth Dynamics of Staphylococcus Aureus In Moroccan Jben Soft Cheese Under Different Storage Temperatures. 16th AgroStat Conference (AgroStat 2024) (AGROSTAT2024), Bragança, Portugal. Zenodo. https://doi.org/10.5281/zenodo.14787843
Abstract
Understanding the growth behavior of pathogens in food products is critical for food safety. This study investigated the growth dynamics of Staphylococcus aureus CECT 976 in Jben goat’s milk soft cheese made without starter culture, and stored at 8°C, 20°C and 37°C. Lab-scale goat’s Jben soft cheese samples were prepared following traditional methods and inoculated with S. aureus strain. Kinetic parameters such as initial and maximum microbial concentrations (SA0, SAmax) and maximum growth rate (μmax SA) were estimated using Lotka-Volterra and Jameson-effect models considering the inhibitory effect (a21) of indigenous lactic acid bacteria (LAB) on S. aureus. The results showed significant temperature-dependent differences in S. aureus and LAB growth rates and maximum concentrations. At 8°C, S. aureus had a lower SA0 and SAmax concentration, and a slower μmax SA (1.054 days-¹, 1.089 days-¹ for Lotka-Volterra and Jameson-effect models). At 37°C, S. aureus showed a significant increase in μmax SA (14.97 days-¹, 22.24 days-¹) and an increase in SAmax. Although the root mean square error (RMSE) and mean absolute error (MAE) values were lower for the Lotka-Volterra model, the fact that a21 was not found significant at any temperature suggested that the Jameson-effect model was a more parsimonious model. Thus, square-root secondary models for the maximum growth rate of S. aureus and LAB were developed from the Jameson-effect fitted values; and subsequently these two relationships were validated against growth data obtained at 30 ºC. These results provide insights into the temperature-dependent growth kinetics of S. aureus in goat’s Jben cheese, which is a first step for ensuring the safety of these regional dairy products.