title: Evaluation of methods to assess the biofilm-forming ability of Listeria monocytogenes.
abstract: The contamination of ready-to-eat products with Listeria monocytogenes has been related to the presence of biofilms in production lines, as biofilms protect cells from chemical sanitizers. The ability of L. monocytogenes to produce biofilms is often evaluated using in  vitro methodologies. This work aims to compare the most frequently used methodologies, including high-throughput screening methods based on microplates (crystal violet and the Calgary Biofilm Device) and methods based on CFU enumeration and microscopy after growth on stainless steel. Thirty  isolates with diverse origins and genetic characteristics were evaluated. No (or low) correlations between methods were observed. The only significant correlation was found between the methods using stainless steel. No statistically significant correlation (P > 0.05) was detected  among genetic lineage, serovar, and biofilm-forming ability. Because results indicate that biofilm formation is influenced by the surface material, the extrapolation of results from high-throughput methods using microplates to more industrially relevant surfaces should be undertaken with caution.
authors.affiliation: Department of Food Science and Technology, University of Georgia, Athens, GA 30602, USA.
authors.forename: António
authors.initials: A
authors.lastname: Lourenço
authors.forename: Francisco
authors.initials: F
authors.lastname: Rego
authors.forename: Luisa
authors.initials: L
authors.lastname: Brito
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Frank
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D015169:Colony Count, Microbial; D008089:Listeria monocytogenes / Q000254:growth & development / Q000502:physiology*; D013193:Stainless Steel
chemical_list: D013193:Stainless Steel