Edible Antimicrobial Films Based on Chitosan Matrix

TLDR

Edible chitosan coatings exhibit strong anti‑Listeria monocytogenes activity on food surfaces, as shown by enumeration and epifluorescence assays. The film’s activity was validated on Emmental cheese using nonpathogenic L. innocua as a model strain.

Abstract

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.