Growth of Staphylococcus aureus 2064 described by predictive microbiology: From primary to secondary models

Alžbeta Medveďová ^*, Adriana Havlíková, Ľubomír Valík

Department of Nutrition and Food Quality Assessment, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava Radlinského 9, Bratislava 812 37, Slovakia

E-mail: ^* alzbeta.medvedova@stuba.sk

Abstract: The growth of Staphylococcus aureus 2064 isolate in model nutrient broth was studied as affected by temperature and water activity using principles and models of predictive microbiology. Specific rates resulting from growth curves fitted by the Baranyi model were modelled by the secondary Ratkowsky model for sub-optimal temperature range (RTKsub) as well as the Ratkowsky extended model (RTKext) and cardinal model (CM) in the whole temperature range. With the biological background of the RTKext model, cardinal values of temperature T_min = 6.06 °C and T_max = 47.9 °C and water activity a_w min = 0.859 were calculated and validated with cardinal values estimated by CM (T_min = 7.72 °C, T_max = 46.73 °C, a_w min = 0.808). CM also provided other cardinal values, T_opt = 40.63 °C, a_{w opt} = 0.994, as well as optimal specific growth rate of 1.97 h^–1 (at T_opt and a_{w opt}). To evaluate the goodness of fit of all models, mathematical and graphical validation was performed and the statistical indices proved appropriateness of all the secondary models used.

Keywords: food safety, prediction, Staphylococcus aureus, temperature, water activity

Full paper in Portable Document Format: acs_0341.pdf

Acta Chimica Slovaca, Vol. 12, No. 2, 2019, pp. 175—181, DOI: 10.2478/acs-2019-0024

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