title: Antibacterial Activity of Neat Chitosan Powder and Flakes.
abstract: This study investigates the antibacterial activity of neat chitosan powder and flakes against three different bacterial species,Escherichia coli,Listeria innocuaandStaphylococcus aureus, which are frequent causes of food spoilage. The effect of chitosan concentration and purity, as well as the influence of temperature, ionic strength (salt) and impact of a solid physical support in the medium are examined. Results show that the antibacterial activity of neat chitosan: (i) requires partial solubilisation; (ii) can be promoted by environmental factors such as adequate temperature range, ionic strength and the presence of a solid physical support that may facilitate the attachment of bacteria; (iii) depends on bacterial species, with a sensitivity order ofE. coli>L. innocua>S. aureus; and (iv) increases with chitosan concentration, up to a critical point above which this effect decreases. The latter may be due to remaining proteins in chitosan acting as nutrients for bacteria therefore limiting its antibacterial activity. These results on the direct use of chitosan powder and flakes as potential antimicrobial agents for food protection at pH values lower than the chitosan pKa(6.2-6.7) are promising.
authors.affiliation: Research Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering, Polytechnique Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, QC H3C 3A7, Canada. nury.ardila@polymtl.ca.
authors.forename: Nury
authors.initials: N
authors.lastname: Ardila
authors.affiliation: Department of Microbiology, Infectiology and Immunology, Pavillon Roger-Gaudry, Université de Montréal, P.O. Box 6128, Station Centre-ville, Montréal, QC H3C 3J7, Canada. france.daigle@umontreal.ca.
authors.forename: France
authors.initials: F
authors.lastname: Daigle
authors.affiliation: Research Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering, Polytechnique Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, QC H3C 3A7, Canada. marie-claude.heuzey@polymtl.ca.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Heuzey
authors.affiliation: Research Center for High Performance Polymer and Composite Systems (CREPEC), Department of Chemical Engineering, Polytechnique Montréal, P.O. Box 6079, Station Centre-Ville, Montréal, QC H3C 3A7, Canada. abdellah.ajji@polymtl.ca.
authors.forename: Abdellah
authors.initials: A
authors.lastname: Ajji
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion / Q000187:drug effects; D048271:Chitosan / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration; D008087:Listeria / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D050296:Microbial Viability / Q000187:drug effects; D009994:Osmolar Concentration; D010316:Particle Size; D011208:Powders; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D013696:Temperature
chemical_list: D000900:Anti-Bacterial Agents; D011208:Powders; D048271:Chitosan
keywords: E. coli; L. innocua; S. aureus; antibacterial activity; chitosan