A 27-year-old Fairfax woman who contracted salmonella poisoning after eating a dinner of veal piccata, Duchess potatoes, Chinese pea pods and raspberry sorbet at Middleburg's Red Fox Inn and Tavern in the spring has filed a $500,000 lawsuit against the restaurant.

In the suit, filed in Fairfax County Circuit Court, Andrea Birnstein said she was afflicted with salmonella poisoning after eating at the inn on April 9, and that she sustained "serious injuries and special damages" as a result.

"We think the culprit was the Duchess potatoes," her attorney, Clifford J. Shoemaker, said yesterday.

He said Birnstein experienced extreme stomach pains and diarrhea and had trouble keeping liquids down. She was hospitalized twice, for a total of about two weeks, and she "still has considerable difficulty with gastro-intestinal problems," he said.

The lawsuit, filed Tuesday, claims that the "conduct of the restaurant was willful, wanton, reckless and in total disregard of public health . . . . " Birnstein is seeking $400,000 in exemplary damages and $100,000 in compensatory damages.

Seven other persons, whose names are not known, became ill with salmonella poisoning in early April, according to Loudoun County health officials. The restaurant closed voluntarily for three days to test its food, procedures and employes.

Salmonella, an organism associated with poultry and eggs, is estimated to affect about 2 million Americans each year. Infected milk was recently suspected as the cause of more than 8,000 such cases in the Midwest, where several deaths were linked to the outbreak.

Turner Reuter, owner of the well-known establishment in the heart of horse country, said yesterday that he was not aware of the suit. But he said he has done everything he can think of to ensure that it will not happen again, including adding hand sinks and disinfectants, testing employes and taking Duchess potatoes off the menu. "We've overreacted," he said.

Reuter said two employes tested positive for the organism and were not allowed to work until they had negative tests. He said one employe was still out, receiving workman's compensation.

Reuter said he has lost none of his regular customers since the incident, though he believes that some people who had never been there may have stayed away after hearing of the problem. Although he said he did have doubts about staying in the business after people became ill, he received letters from patrons expressing their support. "It could happen to anybody," Reuter said.

The Loudoun County Public Health Department is conducting an investigation of the incident. Dr. Earl Virts, director of the department, said yesterday that samples of food and equipment were sent to Richmond for analysis. The final report is still out, he said.

Reuter, who has offered to pay the medical bills of those who were sick, said he suspects eggs were the problem. It was around Easter, he said, when there is a great demand for eggs, which some some companies stockpile for long periods of time.