Characterization of natural antimicrobials utilized for control of Listeria monocytogenes in country-cured hams

A qualitative evaluation study of three cookery methods was conducted to examine cookery effects on eliminating Listeria monocytogenes from long and short cured country ham slices. The heat treatment of the microwave samples effectively eliminated the Listeria monocytogenes, with the convection oven being the least effective heat treatment and the griddle being the most effective to achieve complete elimination of the Listeria monocytogenes cultures. The efficacy of eliminating Listeria monocytogenes from country-cured ham slices is dependent upon time and temperature of the cookery method used.;The ability of Listeria monocytogenes to tolerate antimicrobial treatment by different concentration levels of nisin, Charsol Supreme Poly Hickory liquid smoke (LSP) and Charsol Supreme Hickory liquid smoke (LSL) products in combination with or without steam was investigated on country-cured ham slices and in broth systems. Surface inoculated ham slices treated with nisin and steam had the greatest reduction of Listeria monocytogenes populations (3.72 log10 CFU by 7 days). Nisin was significantly capable of dissipating the Proton Motive Force (PMF) components of Listeria monocytogenes cells regardless of the presence of high concentration salts and nitrite levels. Both liquid smoke products, LSL and LSP, significantly impacted the PMF components by utilizing different modes of action on the cytoplasmic membrane. Results from these studies support the use of natural antimicrobials to extend shelf-life and help to eliminate Listeria monocytogenes from country-cured ham.