Combined Effect of High Pressure Processing with Enterocins or Thymol on the Inactivation of Listeria monocytogenes and the Characteristics of Sliced Dry-cured Ham

Abstract

The effect of high pressure processing (HPP) at 450 MPa for 10 min, enterocins A and B, thymol, and their combinations on the inactivation of a four-strain cocktail of Listeria monocytogenes and the properties of sliced dry-cured ham during 30 days at 4 and 12 °C was investigated. Enterocins A and B initially reduced L. monocytogenes levels by more than 2.5 log units, but a regrowth was recorded during the storage. Individual treatments of thymol and HPP exhibited a low antimicrobial effect against the pathogen. A synergistic antibacterial activity against L. monocytogenes was observed when HPP was combined with enterocins A and B, preventing the recovery of the pathogen during all the storage period. Such combined treatment also maintained total viable counts (TVC) at low levels after 30 days at 4 and 12 °C. Minor changes were detected in pH, aw, color parameters, and shear strength values in dry-cured ham treated with enterocins A and B, thymol, HPP, and their combinations during the storage at both temperatures. Combination of HPP at 450 MPa for 10 min and enterocins A and B might be applied as a hurdle technology, since it reduced L. monocytogenes counts and spoilage bacteria, and slightly affected the characteristics of sliced dry-cured ham