Jay Treadwell has managed to bring continental class to a rigidly non-alcomolic restaurant chain whose clientele would rather be called anything than "gourmets" and whose past reputation has relied predominantly on its bean soup.

Consequently, last year the GAO gave the Senate restaurant system its first clean bill of health in more than 15 years.

The Capitol architect lured Treadwell from Pan Am's food service four years ago to revive senators' flagging appetites for the fare in their dining halls and cafeterias. Until 1978, the Senate's 13-unit food services annually have run in the red at the taxpayers' expense. The tax subsidy for food and supplies reached $623,000 in 1971.

The dining halls still are technically subsidized - heat, room rent and lighting are "free." But last year food services brought a relative profit of $17,000 - the first since 1963.

According to the GAO audit, the "turnaround" resulted from a price increase granted in November, 1977. Lively concession and carry-out sales offset the increased loss on dining hall operations, the report continued.

But Treadwell's campaign to vary the menus has done the most to attract new diners and raise revenues, according to the Capitol's architect's assistant, William Raines. From the beginning, Treadwell assaulted senatorial tastebuds with new entrees and snacks that ranged from "Veal Emincee w/Cucumbers" to Haagen Dazs ice cream and from bagels to nitrite-free bacon. A typical menu in the austere Senate dining halls will feature New Orleans Shrimp Creole, Crepes Florentine, or Asparagus Quiche. And for desert, one may feast on pastries prepared by a chef hired away from the Watergate.

"There was no innovation here at all," before his tenure, Treadwell says. "The same menu had been used for 20 years - timeless boring dishes like sirloin steak, grilled cheese sandwiches, and" - here his face grew dark - "bean soup, the nemesis of all time."

The new offerings have helped boost gross sales to $3.3 million, from about $3.04 million last year and $1.8 million in 1973. The cuisine has been so popular with the "regulars" that at least one senator - Spark M. Matsunaga (D-Hawaii) - habitually lunches four times daily with different groups of constituents, according to Treadwell.

Haagen Dazs alone, of course, cannot a profit make. Treadwell has successfully lobbied two price changes past the Senate Rules Committee since 1977. The last raise before that was in 1973. He also established a bidding system for vendors, replacing the monopoly of years gone by.

Senate operations thus have come into line with those of the House, which have run in the black since 1973. At that time, former Rep. Wayne Hays (D-tohio), as Chairman of the House Administration Committee, brought dining hall finances into order through strict cost accounting and relentless bargaining with suppliers.

Low employe morale has been a problem at both House and Senate restaurants since cafeteria workers struck in 1969. Food service workers now are kept on the payroll all year round, which had been one of their strike demands. And Treadwell strives to "get the employes into it - to make [their jobs] fun."

One may find Treadwell at any mealtime, going through Senate office hallways and cafeterias distributing his newsletter, "The Senate Gastronome," chalking up the daily menu for the new "French Garden" cafe, or carrying some of the bright new yellow T-shirts worn by employes in the garden.

His one regret is that he hasn't yet been able to bring beer or wine to the dining halls. That would easily increase revenue, he noted, but would be "political suicide" for any senator to sponsor. The Senate dining halls went dry during Prohibition, and no legislator since has risked trying to revive a cocktail hour.