Adsorption of biosurfactant on solid surfaces and consequences regarding the bioadhesion of Listeria monocytogenes LO28

Aims: The influence of biosurfactant compounds produced by a strain of Pseudomonas fluorescens on the adhesion of Listeria monocytogenes LO28 to polytetrafluoroethylene (PTFE) and AISI 304 stainless steel surfaces was investigated. Methods and Results: The biosurfactant was produced according to a simple, novel technique based on cultivation on nutrient agar. Adhesion studies were performed using L. monocytogenes cells cultured at 20 or 37 degreesC. Conclusions: A substrate-dependent behaviour of the LO28 strain (larger number of cells adhering to stainless steel than to PTFE), and a significant reduction (< 90%) in microbial adhesion levels through the prior adsorption of biosurfactants on stainless steel surfaces, which can be related to a change in the electron-donor characteristics of this substratum, was demonstrated. Significance and Impact of the Study: The prior adsorption of biosurfactants on solid surfaces may constitute a new and effective means of combating the implantation of pathogenic micro-organisms in food processing plants.