Bacterial inactivation on solid food matrices through supercritical CO2: A correlative study

• Assessed the effectiveness of dense phase CO2 treatment to inactivate different bacterial strains on solid food matrices.
• Investigated the impact of operating conditions on the time evolution of bacterial concentration.
• Mathematical models developed and identified against experimental inactivation data.
• Proposed operational maps illustrating the time required to achieve an assigned inactivation degree.
• Demonstrated the potential of relatively simple models to represent the process.

In this paper the effectiveness of dense phase carbon dioxide (DPCD) treatment to inactivate different bacterial strains inoculated on the surface of solid food matrices is studied. The bacterial survival is investigated on three distinct matrices: Salmonella enterica spiked on fresh cut coconut (Cocos nucifera), Escherichia coli on fresh cut carrot (Daucus carota) and Listeria monocytogenes on dry cured ham surface. Bacterial inactivation experiments are carried out in order to develop and identify mathematical models whose relative performance is assessed in terms of goodness-of-fit and a posteriori statistics obtained after parameters estimation. Operational maps illustrating the time required to achieve an assigned inactivation degree are built in order to guide the choice of the best operating conditions to be used in the process.The results demonstrate the potential of relatively simple correlative models to represent the DPCD pasteurisation process at different experimental conditions, paving the way to more complex model formulation that can be used in DPCD process design and optimisation.