Effect of the pressurizing ramp on the inactivation of Listeria innocua considering thermofluiddynamical processes

Abstract

The effect of the pressurization ramp on the inactivation kinetics of Listeria innocua suspended in Tris buffer has been studied experimentally in an optical pressure cell. Additionally, the thermofluiddynamical processes occurring at the different pressure ramps have been considered. The results obtained at room temperature show that the inactivation effect of high pressure remains the same in case of a fast pressurization ramp (500 MPa/min) and a slow depressurization ramp (100 MPa/min) in comparison to a slow pressurization ramp (100 MPa/min) and a fast depressurization ramp (500 MPa/min). At the chosen test conditions, the fluiddynamical and thermal processes of the two variations differ only slightly from each other. This has been ascertained by measuring the velocity and temperature distributions occurring at the pressure processes. The conclusion is that the pressurization and depressurization rate, respectively, do not effect per se the inactivation kinetics of Listeria innocua.