Influence of temperature on the surface growth of Geotrichum candidum

Growth of filamentous fungus G. candidum was analysed on the surface of skim milk agar as a function of incubation temperature (5 – 37 °C). Radial growth rates of fungus were estimated using growth model of Baranyi which describes the colony diameter as a function of cultivation time. Both Ratkowsky and transformation of G-model were used as secondary models in order to describe the effect of temperature on the radial growth rate of the fungus. Both models proved to be good predictors of G. candidum surface growth within experimental conditions. The bias and accuracy factors were 1.007 and 1.109 for Ratkowsky model and 1.000 and 1.177 for transformed G-model. In presented work also t3 model was proposed which allows the calculation of time needed to reach a colony diameter of 3 mm. This time is important mainly for the practical reasons because such colony would be visible and growth of fungus would be considered as spoilage in specific types of milk products. Due to ubiquitous nature of the fungus and because of its ability to grow at refrigerator temperatures the quantitative results are valuable in respect to the prevention of food spoilage