The effect of nisin on biofilm forming foodborne bacteria using microtiter plate method

Some of pathogenic and food spoilage bacteria can attach on food contact surfaces and form a biofilm, the source of contamination of foods. Biofilm is a functional consortium of microorganisms attached to the surface and is embedded in the extracellular polymeric substances (EPS) produced by the microorganisms. Biofilms due to special structure and EPS are more resistant to antimicrobial agents. Thus control of biofilm formation in food processing is important. Nisin is a peptidic bacteriocin that is used for biocontrol of biofilm formation. The aim of the present study was to assess the effect of various concentration of nisin on biofilm formation of Listeria monocytogenes, Staphylococcus aureus and Salmonella enteritidis. The reduction percent of biofilms was obtained using microtiter plate method and ELISA reader machine. Also, bactericidal effect of nisin was determined by Triphenyl Tetrazolium Chloride. The results indicated that 4?103 IU/ml nisin is more effective on biofilm of S. enteritidis (87%) than L. monocytogenes (57%) and Staph. aureus (30%) with significant difference (P < 0.05).