Predictive model of the effect of temperature, pH and sodium chloride on growth from spores of non-proteolytic Clostridium botulinum.

Non-proteolytic strains of Clostridium botulinum are capable of growth at chill temperatures and thus pose a potential hazard in minimally-processed chilled foods. The combined effect of pH (5.0-7.3), NaCl concentration (0.1-5.0%) and temperature (4-30 degrees C) on growth of non-proteolytic C. botulinum in laboratory media was studied. Growth curves at various combinations of pH, NaCl concentration and temperature were fitted by the Gompertz and Baranyi models, and parameters derived from the curve-fit were modelled. Predictions of growth from the models were compared with data in the literature and this showed them to be suitable for use with fish, meat and poultry products. This model should contribute to ensuring the safety of minimally-processed foods with respect to non-proteolytic C. botulinum.