Nearly 15 percent of Washington's downtown rstaurants in spected in the past two months, including some of the most popular and expensive, received unacceptable sanitation ratings, according to D.C. health officials, who say the city's food industry is getting dirtier.

At the same time, the staff that condicts the inspections of restaurants, grocery stores and food warehouses has been cut in half and is doing only 60 percent of the checks it did five years ago.

The House of Hunan at 1900 K St. NW, a Chinese restaurant widely acclaimed by food critaics, was rated one of the poorst in sanitaiton during the two-month report period reviewed by The Washington Post, scoring only 48 out of a possibl 100 points on June 8. City inspectors cited it an an "imminent danger to public health" and ordered it closed briefly. Hunan empoloyes worked through the night to correct deficiencies and reopened the next day after scoring a 90 on reinspection.

Other well known eatries such as Trader Vics, the Tabard Inn, Joe & Mo's, Gary's and Ponte Vecchio each got a rating of 70, one point above the automatic shutdown score of 69, according to the records. The restaurants were served instead with two-week warnings to correct deficiencies.

Since the first of the year, other popular city restaurants that have received unacceptable health ratings and were given two-week warning notices include the Kennedy Center restaurants (72 points), Vie de France (76), Piccolo Mondo (76), the Greenery (76) and Dominque's (74).

In Georgetown, the heart of the city's dining establishement, restaurants given two-week notices this year include Jour et Nuit (72), Bistro Francais (72), La Ruche (70), Mr. Smith's (70) and The American Cafe (72).

Restaurants scoring below 69 in the unannounced inspections are considered "imminent dangers" and can't reopen until reinspected. Establishments that rank below 85 points get the two-week notices.

Most restaurants cited for deficiencies usually go on crash cleanup campaigns and quickly score passing grades on reinspection, city officials said. They added that most are not only quick but concientious since they are anxious to avoid having their business interrupted.

The purpose of the inspections is not to close restaurants but to make sure "they stay on the ball," one inspector said.

But officials say the trend toward dirtier establishements in the District's 3,700 food service businesses comes at a time when the city's commercial food inspection staff has dropped from 39 to 18 inspectors since 1976 and is facing more reductions over the next two years.

"I can see a dangerous trend," said Arnold K. Clark, who heads the city's bureau of consumer health services, which oversees the inspections. Clark slaid he fears that food businesses are relaxingt their maintenance and sanitation efforts, gambling that the short-staffed inspectors won't be around as often.

Examples of sanitation violations found in various city restaurants this year include rate and mice droppings in kitchen areas and dining rooms, roach infestations, dirty cooking utensils, stoves and other cooking equipment with caked-on grease, improperly stored foods (including one restaurant that had roast beef sitting in a mop basin), broken freezers lwith rotting food, dirty storgage binds and kitchen floors and unsanitary washroom facilities for employes.

"We don't check today's dirt," said one inspector. "It's last week's we're looking for." Clark said the inspectors don't "nit-pick. They have such a heavy work load they just as soon give them 95s and walk out, but if it's very bad, we do something."

To keep tabs on the city's growing restaurants and delicatessens, food inspectors say they are doing fewer checks of the city's gorcery stores and good warehouses. A nationally praised program tht closely monitors fat and bacteria counts in gorcery store ground beef, for example, has been sharply curtialed because of laboratory staff shortges, officials said.

Inspectors aren't even trying to keep with the condition of the city's mechanical vending machines, which they said may number more than 20,000.

And inspectors are just barely getting around to the more than 1,000 street vendors who sell food items. "Vendors are competely out of control," Clark said, "fighting each other, complaining about other operators."

To make things worse, sidewalk cafes, among the most difficult facilities to keep clean, are springing up all over town.

In fiscal 1976, the city's then 39 inspectors made 24,495 food establishement checks. They wrote out 2,815 two-week warnings, or about one for every 8.7 inspections.

In contrast, last year the depleted staff of 18 inspectors condicted 14,944, a drop of 40 percent, and wrote 2,534 warning notices, or about one for every 5.8 inspections.

"I think the warning notices indicate that this is a definite statistical trend . . . toward sanitation deterioration," Clark said. "The establishments are "beginning to slip," he said. He said there also has been a significant increase in the number of establishenments scoring 86, the lowest acceptable rating.

At the same time, public complaints about alleged unsanitary conditions have risen from 605 in 1976 to 1,391 last year, according to records.

Clark said about 23 percent of the city's restaurants were rated poorly 10 years ago, but improved to 11 percent in 1976 and 1977. He said 17 percent failed in 1980. The records reviewed by The Post covered a period from June 1 to July 25 this year and involved 787 downtown restaurants. Of those, 112 ranked unacceptably at 84 points or below, a failure rate of 14.3 percent.

The Tabard Inn at 1739 N St. NW, for example, rated 70 on a July 14 inspection. Owner Edward Cohen did not dispute the city's findings, but said in an interview that his restaurant is located in an older building that is more difficult to maintain. "We are not a $450,000 stainless steel kitchen," said Tabard chef Sarah Ringer.

"No matter what an inspector might find on a gaiven moment, the staff here is extremely concientious about the health of the food and the guests," Cohen said. "You are talking about a restaurant that is open from early in the morning to late at night, seven days a week," Cohen said. "Invariably, things happen that can't be reconciled in good practice."

Cohen said some restaurants "close for a day or two, say they have gone fishing, but really it is a massive cleanup campaign." He said he supports the city's food inspection program. "I doubt if there is another agency as committed as they are."

At the House of Hunan, the recent violations included "live roaches seen throughout premises," and "evidence of mice in basement area," according to the city health reports. The manager was told to seal a vent in a bathroom wall that opened into a dishwashing area. The report also said they "shall be no cleaning of cooking utensils in the mop sink" and "bamboo cups must be replaced. They cannot be clean [sic] in their present state."

Steve Yong, part-owner of the House of Hunan, stressed tht his restaurant scored 90 on the next-day inspection. "We are taking care of the trash outside," referring to one of the complaints in the June 8 report. Johnny Kao, a Hunan manager, said, "We very clean. We constantly clean." He disputed the toilet vent finding, saying it was only a hole in the wall.

The Washington Post employe cafeteria has also been hit recently with a low rating: 70. Inspectors said the cafeteria, among other problems, was not keeping cold and hot foods at proper temperatures.

John Waldren, a sanitation supervisor who has been on the job since the late 1940s, says he has to go an extra step with the inspector shortage to keep the restaurants off guard. "I'll walk by one and tap on the windown and say, "Tomorrow, I'm coming tomorrow.' But," he adds ruefully, "it may be next month."