Indirect additives become part of food in very small quantities as a result of growing, processing, or packaging. Food additives can only be used for specific purposes. They must serve a useful function. Manufacturers cannot use additives to deceive the consumer by disguising faulty processing or concealing damage or spoilage. Nor can food additives be used if they significantly decrease the nutritional value of the food, or if the manufacturer can obtain the desired effect using economical, good manufacturing practices without additives.
Food additives perform a number of functions in food.
For example, vitamins and minerals are added to many common foods like milk, flour, cereal, and margarine to make up for those likely to be lacking in a person's diet or lost in food processing. These can include spices, flavor enhancers, natural and synthetic flavors, and sweeteners. Using food additives enables manufacturers to produce and distribute convenience foods with increased shelf lives and decreased waste. Stabilizers and preservatives make it possible to ship a wide variety of foods all over the world. Nutrient supplementation and enrichment, such as adding iodine to salt, help the nutritional status of those who might not otherwise obtain certain nutrients.