Inactivation of dried spores of Bacillus subtilis 168 by a treatment combining high temperature and pressure

International audience; Specific treatments combining high temperatures of up to 150 °C and moderate pressure of up to 0.6 MPa have been applied to Bacillus subtilis 168 spores conditioned at different aw levels (between 0.10 and 0.70) corresponding to different residual water contents within the spore core. The spores were treated as a dry powder in a pressurized nitrogen environment or in water/glycerol solutions.These thermodynamic conditions were intended to prevent any water evaporation from the spore core during time/temperature treatments.Our results clearly show that retaining liquid water in the core by applying pressure during the treatment resulted in greater spore destruction (b…