The apparent heat-resistance of spores of Bacillus weihenstephanensis and Bacillus licheniformis was measured and expressed as the time to first decimal reduction (δ value) at a given recovery temperature and pH. Spores of B. weihenstephanensis were produced at 30°C and 12°C, and spores of B. licheniformis at 45°C and 20°C. B. weihenstephanensis spores were then heat-treated at 85°C, 90°C and 95°C and B. licheniformis spores at 95°C, 100°C and 105°C. Heat-treated spores were grown on nutrient agar at a range of temperatures (4°C to 40°C for B. weihenstephanensis, 15°C to 60°C for B. licheniformis or a range of pH (between pH 4.5 and pH 9.5 for both strains). The recovery temperature had a low effect on the apparent heat resistance, except very near recovery boundaries. In contrast a decrease in the recovery pH had a progressive impact on apparent heat-resistance. A model describing the heat resistance and the ability to recover according to the sporulation temperature, temperature of treatment and recovery temperature and pH was proposed. This model derived from secondary mathematical models for growth prediction. Previously published cardinal temperature and pH values were used as input parameters. The fitting of the model with apparent heat resistance data obtained for a wide range of spore treatment and recovery conditions, was highly satisfactory.