Evaluation of High Pressure Processing as an Additional Hurdle to Control Listeria monocytogenes and Salmonella enterica in Low-Acid Fermented Sausages

Low-acid fermented sausages (fuet and chorizo) were manufactured to evaluate the combined effect of high pressure processing (HPP) and ripening on foodborne pathogens. Raw sausages inoculated with a three-strain cocktail of Salmonella ser. Derby, London, and Schwarzengrund, and a three-strain cocktail of L. monocytogenes ser. 1/2 c and 4b were pressurized at 300 MPa for 10 min at 17 °C. Afterwards, sausages were ripened at 12 °C and 80% RH for 27 d. Salmonella counts decreased in all studied sausages during ripening. However, the application of HPP as an additional hurdle to the ripening process produced a greater decrease in the Salmonella population, showing lower counts (3 MPN/g) in ripened sausages. By contrast, lower values of L. monocytogenes counts were obtained in non-treated (NT) than in pressurized sausages due to the delay of pH drop caused by HPP inactivation of endogenous lactic acid bacteria. After pressurization of raw sausages at 300 MPa, a discoloration of sausages was observed, coinciding with an increase in L* values.