Modeling the inactivation of psychrotrophic Bacillus cereus spores in beef slurry by 600 MPa HPP combined with 38-70 °C: Comparing with thermal processing and estimating the energy requirements

The growth of psychrotolerant Bacillus cereus in pre-prepared cooked chilled foods and refrigerated processed foods of extended durability (REPFED) is a concern. High pressure processing (HPP) is an established food processing technology that retains the flavor and nutrients in the processed food. In this study, the efficacy of 600 MPa HPP in combination with 70 °C for the inactivation of B. cereus ICMP 12442 spores in beef slurry was investigated and compared with 70 °C thermal processing alone. The HPP-70 °C process enhanced the B. cereus spore thermal inactivation in beef slurry, resulting in 4.9 log reductions after 20 min vs. 0.5 log for thermal processing. Then, the effect of temperature at 600 MPa on the spore inactivation up to 40 min was studied, and the log survivors vs. time were modeled. Weibull model was appropriate to characterize the inactivation. Increasing the HPP temperature from 38 to 70 °C, increased the spore inactivation in beef slurry up to 3 log. Lastly, the thermal inactivation of the spores was investigated. The spore thermal inactivation was linear and first order kinetic parameters were determined. The results of this study confirm the advantage of HPP technology for the inactivation of B. cereus spores in beef slurry at moderate temperatures.