Modelling of microbial growth in potato homogenate system.

GIANNUZZI L.; PINOTTI A.; ZARITZKY NOEMI

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

JOHN WILEY & SONS LTD

Lugar: Londres; Año: 1997 vol. 73 p. 425 - 431

0022-5142

The use of linear and non-linear models (Gompertz and logistic equations) to fit changes in microbial counts in a model system of potato homogenate at various concentrations of chemical preservatives (citric and ascorbic acids) was evaluated. The effect of undissociated acid concentrations (UAC) on k(specific growth rate), lag phase duration and inactivation rate of Enterobacteriaceae, L actobacillus sp, Pseudomonas sp and psychrotrophic microorganisms was determined. Citric acid had a strong inhibitory action on growth rate at low concentrations (0.065 mM UAC, pH\5). Pseudomonas sp were the microorganisms most inhibited by citric acid. Ascorbic acid, at low UAC concentrations (0.302 mM UAC) was more inhibitory to Enterobacteriaceae than to the other microorganisms. For UAC concentration lower than 3 mM, k values of all the microorganisms tested were higher with ascorbic acid than with citric acid ;however at higher concentrations ([10 mM) both acids had similar effects on k.