A simple overall model is proposed to describe the effect of both the pH of the heating menstruum and the pH of the recovery medium on the apparent spore heat resistance of Bacillus cereus. Applied to foods making up both heating and recovery media, the model can be reduced to only two parameters. Its goodness of fit and its robustness enable it to be applied to the optimisation of heat treatments. However. further experiments should be undertaken to validate the model for other species and to determine the parameters related to reference species such as Clostridium botulinum.