The current cleaning methods which are used in the food processing industries are not always sufficient to prevent or remove the Listeria monocytogenes biofilm cells. The formation of the biofilms has enabled the L. monocytogenes to survive in different types of unfavorable conditions hence making the process of eliminating them from such surfaces to be difficult. The poor management of these biofilm cells has therefore led to the development of different challenges regarding the fulfillment of the expected safety and high quality of the food products. This has therefore posed serious health-related threats to the customers. To prevent or limit these risks, it is necessary to ensure food safety in the food processing industries by creating conditions, which do not favor the thriving of the L. monocytogenes on the surfaces of the equipment used in the food processing. In this experiment, the effectiveness of different types of nonionic surfactants such as Pluronic F68, Pluronic F127, Tween 20, Tween 40, Tween 80 and Brij 58 against the Listeria monocytogenes biofilm cells formed on food contact surfaces made of Low-Density Polyethylene (LDPE), Polypropylene (PP), Low-Density Polyethylene and Polypropylene (LDPE-PP), Low-Density Polyethylene and Ethylene Vinyl Acetate (LDPE-EVA), Stainless-Steel and Aluminum was determined. The quantification of the amount of the L. monocytogenes biofilm cells that were destroyed by the nonionic surfactants was done using the Acridine Orange staining (AOS) method after different time intervals of 1, 5, 15 and 30 minutes.

Keywords: Biofilm, Food safety, food contact surfaces, Listeria monocytogenes, surfactant.