Modelling the combined temperature and salt (NaCl) limits for growth of a pathogenic Escherichia coli strain using nonlinear logistic regression

Int J Food Microbiol. 2000 Nov 1;61(2-3):159-67. doi: 10.1016/s0168-1605(00)00352-4.


A 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 degrees 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 degrees C, the temperature range which optimises cell yield. At temperatures below this range the minimum water activity which allowed growth increased with decreasing temperature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Culture Media
  • Escherichia coli / drug effects
  • Escherichia coli / growth & development*
  • Logistic Models
  • Models, Biological
  • Nonlinear Dynamics
  • Sodium Chloride / pharmacology*
  • Temperature*
  • Water


  • Culture Media
  • Water
  • Sodium Chloride