Quantitative analysis of the influence of the substrate and temperature on the growth of the yeast Candida maltosa YP1
2003
Laukova, D.,Vyskumny ustav potravinarsky, Bratislava (Slovak Republic) | Valik, L.,Slovenska technicka univ., Bratislava (Slovak Republic). Fakulta chemickej a potravinarskej technologie
Growth dynamics of an oxidative yeast Candida maltosa Komagata, Nakase et Katsuya in ultra-pasteurized milk (1.5% fat content), ultra-pasteurized cream (30% fat content) and model oil-in-water emulsion (60% fat content) was determined in relation to storage temperature. In all substrates studied, growth of the yeast was observed at 6¦0.5 degree C. With increasing the storage temperature, growth rates were increased and lag-phase shortened for C. maltosa YP1. Maximal growth rate of the strain C. maltosa YP1, m = 0.38/h, equivalently, the minimal generation time, GT = 47 min, and minimal lag-phase duration, l = 2.9 h, were determined in the glucose solution kept at 37 and 25 C (¦0.5 degree C). The increase of growth rate of the yeast C. maltosa YP1 in response to the increasing storage temperature could be, in emulsion substrates, described by the Ratkowsky so called root model and in glucose solution with yeast extract by second-order polynomic equation. The decrease in the natural logarithm of the lag-phase (ln l) of C. maltosa YP1 in relation to the increasing storage temperature was subsequently characterized by linear correlations (Rm2 = 0.9499; Rs2 = 0.9479; Re2 = 0.936). Based on these correlations, predictions on when C. maltosa YP1, as a representative of yeast food contaminants, will reach the density of 1.106 CFU/ml are presented.
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