Destruction of Listeria monocytogenes Biofilms on Stainless Steel Using Monolaurin and Heat ¹

Individual and combined antimicrobial effects of monolaurin and heat on planktonic, 1-day adherent, or 7-day adherent cells of Listeria monocytogenes were determined to evaluate biofilm removal from stainless steel. Planktonic cells were more sensitive to heat and monolaurin than were cells attached to stainless steel. Young (1-day) biofilm cells were more sensitive to each treatment than were old (7-day) biofilm cells. Adherent cells were destroyed by 50 μg/ml monolaurin combined with heating at 65°C for 5 min. Cells in a rich nutrient environment were more resistant to treatment than were cells in a depleted nutrient environment. Results demonstrate the usefulness of combining chemical and physical treatments to control L. monocytogenes biofilm problems in the food industry.