RT Journal Article T1 Effectiveness of Chitosan against Mature Biofilms Formed by Food Related Bacteria A1 Orgaz Martín, Belén A1 Lobete, Maria M. A1 Puga, Carmen H. A1 San José, Carmen AB Chitosan has proven antimicrobial properties against planktonic cell growth. Little is known, however, about its effects on already established biofilms. Oriented for application in food industry disinfection, the effectiveness of both medium molecular weight (MMW) chitosan and its enzymatically hydrolyzed product was tested against mature biofilms of four pathogenic strains, Listeria monocytogenes, Bacillus cereus, Staphylococcus aureus and Salmonella enterica, and a food spoilage species, Pseudomonas fluorescens. Unexpectedly, log reductions were in some cases higher for biofilm than for planktonic cells. One hour exposure to MMW chitosan (1% w/v) caused a 6 log viable cell reduction on L. monocytogenes monospecies mature biofilms and reduced significantly (3–5 log reductions) the attached population of the other organisms tested, except S. aureus. Pronase-treated chitosan was more effective than MMW chitosan on all tested microorganisms, also with the exception of S. aureus, offering best results (8 log units) against the attached cells of B. cereus. These treatments open a new possibility to fight against mature biofilms in the food industry. PB MDPI SN 1422-0067 YR 2011 FD 2011-01-21 LK https://hdl.handle.net/20.500.14352/43080 UL https://hdl.handle.net/20.500.14352/43080 LA eng NO Ministerio de Ciencia e Innovación (MICINN) NO Comunidad de Madrid DS Docta Complutense RD 8 abr 2025