title: Characterisation of biofilms formed by Lactobacillus plantarum WCFS1 and food spoilage isolates.
abstract: Lactobacillus plantarum has been associated with food spoilage in a wide range of products and the biofilm growth mode has been implicated as a possible source of contamination. In this study we analysed the biofilm forming capacity of L. plantarum WCFS1 and six food spoilage isolates. Biofilm formation as quantified by crystal violet staining and colony forming units was largely affected by the medium composition, growth temperature and maturation time and by strain specific features. All strains showed highest biofilm formation in Brain Heart Infusion medium supplemented with manganese and glucose. For L. plantarum biofilms the crystal violet (CV) assay, that is routinely used to quantify total biofilm formation, correlates poorly with the number of culturable cells in the biofilm. This can in part be explained by cell death and lysis resulting in CV stainable material, conceivably extracellular DNA (eDNA), contributing to the extracellular matrix. The strain to strain variation may in part be explained by differences in levels of eDNA, likely as result of differences in lysis behaviour. In line with this, biofilms of all strains tested, except for one spoilage isolate, were sensitive to DNase treatment. In addition, biofilms were highly sensitive to treatment with Proteinase K suggesting a role for proteins and/or proteinaceous material in surface colonisation. This study shows the impact of a range of environmental factors and enzyme treatments on biofilm formation capacity for selected L. plantarum isolates associated with food spoilage, and may provide clues for disinfection strategies in food industry.
authors.affiliation: Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University and Research Centre, Bornse Weilanden 9, 6700 AA Wageningen, The Netherlands.
authors.forename: Mónica D
authors.initials: MD
authors.lastname: Fernández Ramírez
authors.affiliation: Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University and Research Centre, Bornse Weilanden 9, 6700 AA Wageningen, The Netherlands.
authors.forename: Eddy J
authors.initials: EJ
authors.lastname: Smid
authors.affiliation: Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University and Research Centre, Bornse Weilanden 9, 6700 AA Wageningen, The Netherlands. Electronic address: Tjakko.Abee@wur.nl.
authors.forename: Tjakko
authors.initials: T
authors.lastname: Abee
authors.affiliation: Top Institute Food and Nutrition (TIFN), Nieuwe Kanaal 9A, 6709 PA Wageningen, The Netherlands; Wageningen UR Food and Biobased Research, Bornse Weilanden 9, 6700 AA Wageningen, The Netherlands.
authors.forename: Masja N
authors.initials: MN
authors.lastname: Nierop Groot
mesh_terms: D018407:Bacterial Physiological Phenomena / Q000187:drug effects; D018441:Biofilms / Q000187:drug effects; D005525:Food-Processing Industry / Q000379:methods*; D005840:Gentian Violet / Q000378:metabolism; D048191:Lactiplantibacillus plantarum / Q000187:drug effects / Q000502:physiology*; D010447:Peptide Hydrolases / Q000494:pharmacology; D013696:Temperature
chemical_list: D010447:Peptide Hydrolases; D005840:Gentian Violet
keywords: Biofilm; Dispersion; Food spoilage; Lactobacillus plantarum