Breakfast Sticker Shock

NOT everyone in Washington spends all his time worrying about how to hasten, or hinder, the Contract With America. Reps. Charles Schumer of New York and Sam Gejdenson of Connecticut, for instance, recently called on the Justice Department to investigate possible price fixing by the makers of breakfast cereals.

Showing that his antennae extend far beyond the beltway, Mr. Schumer described his ''outrage'' at finding prices of $4 and up on overpackaged, overpromoted concoctions of wheat, corn, rice, and oats. These prices are ''a pet peeve you wish you could do something about,'' inveighed the lawmaker.

As a member of Congress, of course, he can do something -- if it's only to sound off. Schumer's press release on the subject pointed out that 85 percent of cereal sales are controlled by four companies -- Kellogg, General Mills, Post, and Quaker Oats. Since 1983, he contended, cereal prices have gone up 90 percent, twice the increase of other foods.

Schumer calculated that Americans would have saved $1.7 billion last year if wheat-flake and corn-puff prices had stayed even with inflation.

The Grocery Manufacturers of America responded with a crisp statement suggesting that the congressman's figures, not their prices, are inflated. They rest their case on a United States District Court decision in February, which found that cereal prices in recent years have actually stayed below the rate of inflation and that the industry is highly competitive. That ruling crunched a lawsuit brought against the cereal makers by New York's attorney general.

The judge's ruling aside, Schumer and Gejdenson are on to something. While the manufacturers' insist that cereal remains a great bargain at 25 to 30 cents a ''serving'' (certainly not the heaping bowlfuls favored by some eight-year-olds we know), most shoppers are probably as shocked as the congressmen at the price of a box of raisin bran.

If the call for a federal probe quickly goes soggy, the public at least has a recourse to coupons or store brands. And real radicals can stage the ultimate protest: a return to bulk-bought oatmeal.TX: