Influence of water activity and acidity on Bacillus cereus spore inactivation during combined high pressure-thermal treatment

Understanding the inactivation kinetics of bacterial spores during combined pressure-thermal processing is essential for process design. The knowledge on influence pH and water activity ( a w ) treatment limited. Experiments were conducted using Bacillus cereus suspended in citrate-phosphate buffers, adjusted to different levels (3.8–7.3) (0.80–0.99). Spores then treated with pressure-heat combination (600 MPa, 70 °C) laboratory-scale high-pressure kinetic tester. Linear regression Weibull models used fit experimental data. parameters estimated from plotted as function . Results showed that curves characterized by tailing, particularly at low levels. log reduction B. decreased decrease During treatment, changes acidity values given have limited decimal spores. Study findings will be helpful designing processes produce microbially safe products varying • Influence spore 600 MPa/70 °C was studied. Acidic condition enhanced lethality treatment. Inactivation pronounced tailing.