Lactic acid is a natural organic acid with a long history in the food, leather, wool-dyeing and cosmetics industries. Long before it became commercially available, lactic acid was formed by natural fermentation in products such as cheese, yogurt, soy sauce, sourdough, meat products, pickled vegetables, beer and wine. Animal and human bodies also produce significant amounts of lactic acid during daily activities such as walking and running. Today, lactic acid, its salts and esters are extensively used in food, industrial, cosmetic and pharmaceutical industries.