Letheen Broth Base, Modified is a liquid medium used to determine the antimicrobial activity of quaternary ammonium compounds. Lecithin, Tween80, and Sodium Bisulfite neutralize quaternary ammonium compounds, phenols, and formalin present in cosmetic products. Meat Peptone, Beef Extract, Yeast Extract, and Enzymatic Digest of Casein provide nitrogenous compounds, carbohydrates, vitamins and minerals. Sodium Chloride maintains osmotic equilibrium.