In the wake of rising concern that children may be eating too much sugar, there has been a rash of anti sugar-coated cereal actions in the last two months. A billion-dollar class action has been filed against General Foods, a public interest group is seeking a ban on a cereal commercial, and the Canadian government has told cereal manufacturers to list the amount of sugar their products contain.

A tiny San Francisco public-interest law firm has filed the lawsuit against General Foods on behalf of a coalition of California consumer groups. It charges the company with false adversiting, fraud and unfair business practices.

The suit claims that five Post cereals are from 38 to 47 per cent sugar, or more than soda pop (4.2 per cent) or candy bars (the percentage of sugar in a Milky Way is 28.8). (According to research done by Dr. Ira Shannon, reported in the September-October 1974 issue of Journal of Dentistry for Children, three of the Post Cereals named in the suit actually are more than 47 per cent sugar: Cocoa Pebbles (53.5), Fruity Pebbles (55.1) and Honeycomb (48.8). Super Sugar Crisp contains 40.7 per cent, Alpha Bits 40.3.

An attorney for the law firm, Sidney Wolinsky, said the suit was filed because, "Pitching food products to children on TV is like shooting fish in a barrel. They're creating a nation of sugar-junkies with a sugar habit."

The suit, which calls the five cereals "candy breakfasts," claims that the company's advertising campaigns "blur the distinction between fantasy and reality to the point where children cannot distinguish" facts from fantasy.

It asks the court to stop the company from advertising these cereals as "part of a balanced breakfast."

A General Foods spokesman has said the company is "in total disagreement with the charges.We think they're wrong and we're right."

Meanwhile, in Boston, Action for Chidlren's Television (ACT) is seeking a ban on television commercials for a new cereal from Ralston Purina. The cereal is called Cookie Crisp and is at least 46 per cent sugar.

In its petition to the Federal Trade Commission, ACT asserted that the advertising for the cereal "creates for the child the net impression that it is nutritionally desirable to consume cookies for breakfast."

The commercials for the creal show an animated character-spokesman, "Cookie Jarvis," who transforms children's cereal bowls into cookie jars. The same figure is used on the boxes of Cookie Crisp, which show the cookie-shaped cereal in a large cookie jar.

In the commercial, Cookie Jarvis describes the product as "shaped like little cookies from a cookie jar" and sayd it "taste(s) like sweet crunchy cookies."

While the $1-billion law suit is before the courts and the FTC is weighing whether or not it should ban the Cookie Crisp commercials, the Canadian government is moving ahead with its plans to require labeling on breakfast cereals that would indicate how much sugar and other sweeteners these products contain. Proposals to require similar labeling of cereals in the United States have been before the Food and Drug Administration for several years. Two cereal manufacturers are listing the sugar content of their cereals in grams per serving, but consumers have a difficult time translating the measure into meaningful terms.