10.22376/ijpbs.2019.10.1.p1-12 Volume 6 Issue 1 2015 (January - March) The antimicrobial effect of the polyamide 6/66-chitosan blend obtained by extrusion and chitosan-coated plastic films was compared with pure chitosan films and chitosan solution against lessThan i greaterThan Escherichia coli lessThan /i greaterThan , lessThan i greaterThan Listeria monocytogenes lessThan /i greaterThan and lessThan i greaterThan Bacillus cereus lessThan /i greaterThan . The films from polyamide 6/66-chitosan blend had no antibacterial activity, and the chitosan plastic film coating (bilayer system) showed only contact inhibition, without increase of contact area. The pure chitosan films did not show inhibition halos, however, contact inhibition was observed. During the assays, this films absorbed moisture, increasing the diameter of the discs at least 30%, causing contact inhibition on the area in all microorganisms tested. The best inhibition effect was observed with chitosan solution, reaching the total inhibition for lessThan i greaterThan Listeria monocytogenes lessThan /i greaterThan and a log reduction of 3.6 and 2.3 for lessThan i greaterThan Escherichia coli lessThan /i greaterThan and lessThan i greaterThan Bacillus cereus, lessThan /i greaterThan respectively. Chitosan has an antimicrobial effect, although this property was reduced by the incorporation of a plastic matrix. DALIA I. SÁNCHEZ-MACHADO, JAIME LÓPEZ-CERVANTES AND JESÚS R. RODRÍGUEZ-NÚÑEZ Antimicrobial films, chitosan, inhibition halos, physicochemical properties, coating. 204-212