The Department of Agriculture's controversial "junk food" regulation governing what can be sold in school vending machines will be in the courts before it is ever in force.

The regulation was announced last Friday, and the only reason the first court challenge wasn't filed the same day was because the regulation wasn't signed until after the courts had closed for the weekend.

On Monday a consumer coalition led by the Community Nutrition Institute (CNI) asked that the regulation be amended to get rid of the "loopholes" and make it "consistent with the intent of Congress." According to CNI's Ellen Haas, Congress wants the foods sold in scholls to "make a nutritional contribution to the diet and dietary habits."

Haas says the current regulation permits the sale of many foods that do not meet these criteria.

The new regulation is USDA's second attempt to control the kinds of foods children can eat in school which compete directly with what is served in the school lunch program. These are the foods usually sold in vending machines.

The new ban covers soda pop, water ices, chewing gum and candies such as marshmallow, corn candy and hard candies -- but candies that contain chocolate, for example, would not be banned. Potato chips, pretzels, fruit-flavored juice drinks, even such products as Kool-Aid are not included in the ban.

Any food that contains 5 percent of the recommended daily allowance of just one of eight nutrients is deemed acceptable under the new regulation.

Asked if a manufacturer couldn't simply fortify food or drink with 5 percent of any single nutrient and then qualify, Assistant Agriculture Secretary Carol Foreman said the new FDA proposal on food fortification will make that impossible.

FDA has just announced a proposal governing the fortification of foods. According to the proposal: "FDA . . . believes it is inappropriate to fortify snack foods such as candies and carbonated beverages."

The USDA regulation is scheduled to take effect July 1, 1980, which mea that schools would have to comply by the beginning of the next school year. But court challenges may delay implementation.

In the Washington area only Arlington County would feel the effects. Most of the local school systems have already eliminated candy and soda pop as well as some other snacks, from theirschool vending machines.