Lactic acid is used as acid or sodium and potassium salts up to 2% in carbonated drinks, salad dressings, pickled vegetables, low-heat-processed meat products, and sauces. It is less effective than acetic, propionic, benzoic, or sorbic acids, but more effective than citric acid. It is more effective against bacteria but quite ineffective against yeasts and molds. It produces an inhibitory effect mainly by neutralizing the membrane proton gradient. The sodium salt of lactic acid may also reduce Aw.L(+)-lactic acid is preferred over D(–)-lactic acid as a food preservative. It has also been recommended at a 1 to 2% level to wash carcasses of food animals to reduce microbial load