Food additives are chemicals that when added to food, contribute to improve its shelf life, safety, appearance and flavor, so that the foods we eat still have a consistently high quality. In some products, they are so essential that additives are used even in certain organic foods. They may also improve the nutritional value of certain foods. Almost all of processed foods contain additives, substances intended to change the food in some way before it is sold to consumers. In Europe, all permitted food additives have been given a number beginning with E, so that they can easily be shown on food labels.