Modeling the kinetics of survival of Staphylococcus aureus in regional yogurt from goat's milk

Abstract

The aim of this study was to determine the kinetics of the survival of the test strain of Staphylococcus aureus in the product investigated. Yogurt samples were contaminated with S. aureus to an initial level of 10 3 -10 4 cfu/g. The samples were then stored at four temperatures: 4, 6, 20, 22 o C.During storage, the number of S. aureus forming colonies in a gram of yogurt was determined every two hours. Based on the results of the analysis culture the curves of survival were plotted. Three primary models were selected to describe the kinetics of changes in the count of bacteria: Cole's model, a modified model of Gompertz and the model of Baranyi and Roberts. Analysis of the model fit carried out based on the average values of Pearson's correlation coefficient, between the modeled and measured values, showed that the Cole's model had the worst fit. The modified Gompertz model showed the count of S. aureus as a negative value. These drawbacks were not observed in the model of Baranyi and Roberts. For this reason, this model best reflects the kinetics of changes in the number of staphylococci in yogurt.

Modeling the survival of Salmonella Enteritidis and Salmonella Typhimurium during the fermentation of yogurt

“…With predictive microbiology models, the behavior of microorganisms under specific environmental conditions can be predicted throughout the food supply chain (Pérez-Rodríguez and Valero, 2013), in particular to perform or validate control measurements. Although pathogen behavior in yogurt has been investigated by several researchers (Akkaya et al., 2009; Al-Haddad, 2003; Álvarez-Ordóñez et al., 2012; Bachrouri et al., 2002; Canganella et al., 1999; Massa et al., 1997; Ogwaro et al., 2002; Pazakova et al., 1997), there are only few predictive modeling studies available in the literature (Bednarko-Młynarczyk et al., 2015; Szczawiński et al., 2014). To the best of our knowledge, these studies only focus on modeling the effect of the storage process, not addressing pathogen survival during fermentation.…”

Yoğurt Fermantasyonu Sirasinda Salmonella Enteritidis’i̇n Farkli İnokülasyon Koşullarinda Canli Kalma Durumunun Araştirilmasi

“…Bu nedenle önemli g›da patojenlerinin neden oldu¤u hastal›klar›n önlenebilmesi için, bu patojenlerin g›da içindeki davran›fllar›n›n araflt›r›lmas› gerekmektedir. Literatürde yo¤urdun fermantasyonu ve depolamas› s›ras›nda patojen geliflimi ile ilgili pek çok çal›flma yap›lm›fl olsa da (6)(7)(8)(15)(16)(17)(18) yo¤urtta Salmonella davran›fl›n›n incelendi¤i çal›flmalar oldukça s›n›rl›d›r (13,19,20).…”