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Modelling the growth limits (growth/no growth interface) of Escherichia coli as a function of temperature, pH, lactic acid concentration, and water activity
journal contribution
posted on 2023-05-16, 11:20 authored by Presser, KA, Thomas RossThomas Ross, David RatkowskyDavid RatkowskyThe fore of a previously developed Belehradek type of growth rate model was used to develop a probability model for defining the growth/no growth interface as a function of temperature (10 to 37°C), pH (pH 2.8 to 6.9), lactic acid concentration (0 to 500 mM), and water activity (0.955 to 0.999; NaCl was used as the humectant). Escherichia coli was unable to grow in broth in which the undissociated lactic acid concentration exceeded 11 mM or, with two exceptions, at a pH of 3.9 or less with no lactic acid present. Under experimental conditions at which the pH and the undissociated acid concentrations were the major growth-limiting factors, the growth/no growth interface was essentially independent of temperature at temperatures ranging from 15 to 37°C. The interface between conditions that allowed growth and conditions at which growth did not occur was abrupt. The inhibitory effect of combinations of water activity and pH varied with temperature. Predictions of the model for the growth/no growth interface were consistent with 95% of the experimental data set.
History
Publication title
Applied and Environmental MicrobiologyVolume
64Issue
5Pagination
1773-1779ISSN
0099-2240Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
American Society of MicrobiologyPlace of publication
Washington DCRepository Status
- Restricted