Additives that are added to a food for a specific purpose are known as direct additives. For example, the low calorie sweetener, aspartame, is a direct additive that is added to puddings, soft drinks, yogurt, and many other foods. Direct additives are identified on a food's ingredient label. Indirect additives become part of the food in very small amounts during the processing, packaging, or storage of the food item. By law, manufacturers must document that the amounts present are considered so insignificant as to be safe.
Examples are the addition of Vitamin D to milk and vitamins A and D to margarine.
Examples of this additive include cornstarch added to powdered sugar to prevent lumping and leavenings to make baked products rise. The use of phosphate additives in instant oatmeal or instant pudding is an example. Artificial or synthetic colors and flavors are examples of this type of additive. These additives are added in minute amounts that can have a large impact. The Food, Drug, and Cosmetic Act of 1938 and its 1958 and 1960 amendments give the FDA regulatory authority over food additives.