NOT MEANING to make an excessive fuss about a mere fly in our soup, it is nonetheless rather unappetizing to learn that one District restaurant keeps roast beef in a mop bucket. This in sight was afforded by a review of the records of the Bureau of Consumer Health Services by Post staff writer Tom Sherwood. According to city officials, about 15 percent of the city's restaurants have received an unacceptable sanitation rating in the past two months. These include the Kennedy Center restuarants, House of Human and Dominique's. The Post cafeteria missed this ignomy by one point.

Many restaurants were not closed, but instead received notices to place by their-entrance telling patrons that the restaurants had two weeks to rectify poor sanitation. In almost all cases, restaurants cleaned up quickly, and the signs disappeared. But these incidents should not be taken lightly. This week at Providence Hospital, a city official reports, a pregnant woman suffering from anemia was found to have three different internal parasites, including hook worm. These parasites are transmissible through food. Similary, tuberculosis can be passed through food, and this is a point of real concern in the District, which has the second highest rate of TB in the nation.

Officials can rarely prove that an illness was caused by food eaten at a given restuarant. People often cannot recall what they ate and where. But 38 people complained in the first half of this year to the city government that they were made ill by food from city restaurants, a slight increase over the same time last year.

Compounding the problem is the reduction in the number of city workers to inspect the restaurants. Every restuarant in the city is supposed to be inspected once every three months. However, no restaurants were inspected in the last three months of last year, according to Arnold K. Clark, chief of the Bureau of Consumer Health Services, and 20 percent of the restaurants were not inspected for six months. The cause was a drop in the number of inspectors from 38 in 1977 -- to 13 today.

Mr. Clark says inspections of all restaurants will be made on time this year, at a cost of less attention to fish markets, supermarkets and food processing plants. This is a gamble with the health of residents and visitors. The city government needs to consider reorganizing its staff to permit necessary inspections in all businesses that handle food.