Antimicrobial activity of chitosan films containing nisin, peptide P34, and natamycin

The antimicrobial effect of edible chitosan films containing nisin, peptide P34, and natamycin was investigated. The activity of chitosan films was tested against Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, Clostridium perfringens, Lactobacillus acidophilus, Aspergillus phoenicis, and Penicillium stoloniferum. The addition of nisin and P34 significantly increased the activity against bacteria. Films containing natamycin showed similar inhibition than those with chitosan alone. Chitosan films were effective to control microbial growth in minimally processed pear. Fourier transform infrared spectra of the films were similar, indicating the absence of relevant interaction between the polymer and the antimicrobial agent. The films were also analyzed by scanning electron microscopy to visualize the surface topography. Chitosan films were rough and heterogeneous. The incorporation of antimicrobials agents to edible chitosan films or covering may be a feasible and attractive method for food biopreservation.