Kerri Phebus, age 8, of Sarasota, Fla., for her question:

WHY ARE ADDITIVES PUT IN FOOD?

An agency of the U.S. Department of Health, Education and Welfare called the Food and Drug Administration (FDA) enforces the federal laws designed to ensure the purity of food, the safety and effectiveness of drugs and therapeutic devices and also the safety of cosmetics.

Any chemical that food manufacturers add to their products is called a food additive. Some are put in to increase a food's nutritional value, and others are added to improve the texture, color or flavor of foods. Another common additive put into foods is used to keep it from spoiling.

Hundreds of different additives are used by food manufacturers for their products. There are six major groups of additives: preservatives; nutritional supplements; flavoring agents; coloring agents; emulsifiers, stabilizers and thickeners; acids and alkalis.

Preservatives called antioxidants are used to keep oils and fats from spoiling and also to prevent other foods from becoming discolored. Other preservatives are used to prevent the growth of bacteria.

Some food items receive iron, minerals and vitamins to make the items more nourishing. Flour is one of the products often improved nutritionally this way, as is milk. Spices, natural fruit flavors and many man made flavors are added to other products to improve their appeal.

Synthetic food coloring is used to replace natural colors that might have been lost in the processing. Color is also used to make synthetic food resemble the real ones.

Carrageen is the most widely used stabilizer and it keeps chocolate particles in chocolate milk from settling,

while pectin and gelatin are used to thicken jams and jellies. An emulsifier named algin is used to give ice cream its creamy texture and to maintain the liquids in salad dressing.

Alkalis are used to neutralize the high acid content in such canned foods as olives and peas, while citric acid is a added to fruit juice to give it a tart taste. Carbonic acid is used in soft drinks to provide the fizz.

A dye used in foods, drugs and cosmetics called Red No. 2 was banned by the FDA in 1976 after tests indicated that it could cause cancer inrats. In 1970 another famous case came before the FDA with the prohibition of the sale of an artificial sweetener called cyclamate. This additive was also found to cause cancer in laboratory animals when consumed in large amounts.

Food additives, the FDA assures us, are safe for human consumption.