Supercritical Carbon Dioxide Processing of Dry Cured Ham Spiked with Listeria monocytogenes: Inactivation Kinetics, Color, and Sensory Evaluations

Abstract

The feasibility of supercritical carbon dioxide (SC-CO2) treatment to inactivate Listeria monocytogenes inoculated on the surface of dry cured ham was investigated. A multibatch apparatus was used. Inactivation kinetics were determined at 8 and 12 MPa, as a function of temperatures (35–50 °C), treatment times (5–60 min), and initial microbial loads (103–107 colony-forming units [CFU]/g). Color changes of the sample were determined by measuring the reflectance spectra and L*, a*, and b* parameters. A new spectroscopic technique was developed for this. Sensory quality of the product before and after the SC-CO2 treatment was evaluated by a sensory panel. Treatment at 50 °C, 12 MPa for 15 min resulted in total inactivation of L. monocytogenes with an initial microbial load of 107 CFU/g. Less severe conditions, e.g., 45 °C, 12 MPa, 5 min, were sufficient to reach total inactivation if the initial microbial load was 103 CFU/g. The process slightly influenced the color and sensory attributes of the sample. The results demonstrated the efficiency and the potential of SC-CO2 as a technology for the pasteurization of the surface of foods, in particular ham-type meat products.