(494f) Supercritical Carbon Dioxide Inactivation of Listeria Monocytogenes Spiked On Dry Cured Ham Pig Skin

Supercritical carbon dioxide (SC-CO₂) treatment has been largely demonstrated to be a promising preservation method for liquid foods as it induces microbial inactivation avoiding undesirable alternations of quality and nutritional attributes. Due to the high potentials of the process, the research has been recently turned into the applications of SC – CO₂ treatment to solid foods.

In this concern, a feasibility study of SC-CO₂ treatment for the inactivation of Listeria monocytogenes one of the most important foodborne pathogen detected along the dry cured ham processing chain and affecting the quality and safety of the product is presented.

Dry cured ham pig skin, spiked with L. monocytogenes (ATCC19115), is treated in a multi – batch lab scale apparatus at 12.0 MPa and the inactivation kinetics determined as a function of temperature (35¸50°C), treating time (5¸30 minutes) and microbial load (10⁷ cfu·g^-1 and 10³ cfu·g^-1). Additionally, an innovative spectroscopic technique is exploited to detect in-line color modifications of the sample during the process at the different operative conditions in terms of reflectance spectra and L^*, a^*, b^* parameters.

The results show that 1. a treatment at 50°C, 12.0 MPa for 15 minutes induces total inactivation of L. monocytogenes with an initial load of 10⁷ cfu·g^-1, while less severe processing conditions of 45°C, 5 minutes of treatment are necessary if the initial load is decreased down to 10³ cfu·g^-1, 2. the SC-CO₂ process does not induce significant changes in color parameters (L^*, a^*, b^*).

The resulting data clearly demonstrate the efficiency of the process, suggesting SC-CO₂ as an innovative technology for the pasteurization/sterilization of solid food products.

 

The research leading to these results has received funding from the European Community’s Seventh Framework Program (FP7/2007-2013) under grant agreement no. 245280, also known under the acronym PRESERF.