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Modelling the combined temperature and salt (NaCl) limits for growth of a pathogenic Escherichia coli strain using nonlinear logistic regression
journal contribution
posted on 2023-05-16, 12:09 authored by Salter, MA, David RatkowskyDavid Ratkowsky, Thomas RossThomas Ross, Thomas McMeekinThomas McMeekinA broth-based method is used to determine if exponential phase Escherichia coli R31, an STEC, is able to grow within 50 days under various combinations of sub-optimal temperatures and salt concentrations. From these data, the growth limits for combinations of temperature (7.7-37.0°C) and water activity (0.943-0.987; NaCl as humectant) are defined and modelled using a nonlinear logistic regression model. That form of model is able to predict the combinations of salt concentration/water activity and temperature that will prevent the growth of E. coli R31 with selected levels of confidence. The model fitted the data with an approximate concordance rate of 97.3%. The minimum water activity that permitted growth occurred in the range 25-30°C, the temperature range which optimises cell yield. At temperatures below this range the minimum water activity which allowed growth increased with decreasing temperature.
History
Publication title
International Journal of Food MicrobiologyVolume
61Issue
2-3Pagination
159-167ISSN
0168-1605Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Elsevier Science BVPlace of publication
Amsterdam, NetherlandsRepository Status
- Restricted