Edible Antimicrobial Films Based on Chitosan Matrix

ABSTRACT: : Edible chitosan coatings showed anti‐ Listeria monocytogenes effect evaluated by numeration and epifluorescence methods, imparting a strong localized functional effect at the food surface by active packaging. The use of film‐forming solution in culture liquid medium showed a known flocculant phenomenon combined with bactericidal activity, keeping 20% of the initial microbial charge as viable cells in flocculant, which could develop subsequently. However, chitosan film showed 100% of L. monocytogenes inhibition for at least 8 d, completed by bactericidal activity measured by epifluorescence assays. A decrease in antibactericidal effect with time was obtained, most probably due to a decreasing availability of amino‐groups of chitosan. Latter results were validated on Emmental cheese samples using L. innocua as model strain because of its nonpathogenicity.