Influence of temperature on biofilm formation by Listeria monocytogenes on various food-contact surfaces, relationship with motility and cell surface hydrophobicity

Aims: To assess the ability of Listeria monocytogenes to form biofilm on differentfood-contact surfaces with regard to different temperatures, cellular hydrophobicityand motility.Methods and Results: Forty-four L. monocytogenes strains from food and foodenvironment were tested for biofilm formation by crystal violet staining. Biofilmlevels were significantly higher on glass at 4, 12 and 22C, as comparedwith polystyrene and stainless steel. At 37C, L. monocytogenes produced biofilmat significantly higher levels on glass and stainless steel, as compared withpolystyrene. Hydrophobicity was significantly (P < 0Æ05) higher at 37C than at4, 12 and 22C. Thirty (68Æ2%) of 44 strains tested showed swimming at 22Cand 4 (9Æ1%) of those were also motile at 12C. No correlation was observedbetween swimming and biofilm production.Conclusions: L. monocytogenes can adhere to and form biofilms on food-processingsurfaces. Biofilm formation is significantly influenced by temperature,probably modifying cell surface hydrophobicity.Significance and Impacts of the Study: Biofilm formation creates major problemsin the food industry because it may represent an important source of foodcontamination. Our results are therefore important in finding ways to preventcontamination because they contribute to a better understanding on howL. monocytogenes can establish biofilms in food industry and therefore survivein the processing environment.[...]