The city has filed a lawsuit threatening to shut down Joy Tsin Lau, the Chinatown mainstay where nearly 100 attorneys and law students were sickened in February in one of Philadelphia's largest reported outbreaks of foodborne illness.

The victims, many of them personal-injury lawyers, were laid low for several days with severe vomiting and diarrhea after attending a fundraising banquet at the restaurant. A spokesman for the city health department said the diners' distress was likely caused by a norovirus.

In the court filing, dated May 6, the city deems Joy Tsin Lau a "serious and immediate hazard" and "a public health nuisance." It asks the Common Pleas Court to issue Joy Tsin Lau a cease and desist order for failing to address numerous health violations.

The suit follows three years of inspection reports portraying Joy Tsin Lau as chronically failing to meet basic health standards.

When first contacted by a reporter Monday about the pending suit, Joy Tsin Lau's owner, Mabel Chi Chan, said she was stunned. She said the health department last visited her restaurant on April 18, two days after the last failed inspection, and granted it permission to reopen. A friend of Chan's provided Philly.com with a copy of the report, which was not yet in the public record. It indicated a clean facility with no violations.

"They said everything was 100 percent OK," said Chan, on the verge of tears. "I don't understand. When the health department says something is not right, we change it. We do everything to be right."

Beverly L. Penn, senior attorney for the city, said she could not comment about the matter.

"The suit speaks for itself," Penn said.

Chan, a well-known neighborhood figure and philanthropist, has operated Joy Tsin Lau on Race Street near 10th for more than three decades. Chan said business dropped off after news of the Lunar banquet became public.

"Our employees are very nice people with families," she said. "It's been very hard; they don't know English. The health department came to teach us how to clean up the restaurant. They said we're doing good now."

Thomas Betz, a friend of Chan's and pastor of the Holy Redeemer Chinese Catholic Church in Chinatown, said the lawsuit makes little sense.

"The Health Department found no health violations on its most recent inspection of Joy Tsin Lau. Nevertheless, a few weeks after giving Joy Tsin Lau a perfect health inspection report, the Health Department has filed suit asking that the restaurant be closed until it corrects all health violations.

"It seems to be a deliberate effort to destroy Chinatown's most beloved and venerable restaurant," Betz said.

The city has threatened to close Joy Tsin Lau several times during the last decade. Each time, the action was withdrawn after the restaurant was found in compliance.

It's unclear if the Feb. 27 outbreak of food poisoning played a role in the city's filing suit.

But three earlier inspections are noted in the city's suit. One report, dated Feb. 10, two weeks before the outbreak, found serious violations including a lack of soap in the employee restroom, inaccessible handwashing sinks, and food held at unsafe temperatures.

One week after the banquet, on March 2, the city health department sent another inspector to Joy Tsin Lau. During the visit, the inspector cited 41 violations that included mouse droppings on work tables, chicken feet thawed improperly, food held at bacteria-friendly temperatures, and cooks who did not properly wash their hands.

The inspector asked Joy Tsin Lau to close until it could comply with the health code. The restaurant was dark for a less than a day. On March 3 the health department allowed it to reopen.

This week, the health department released the findings of an April 16 follow-up inspection. On that visit, sanitarian Stephen Belo uncovered 35 violations.

Belo, who spent 4-1/2 hours on site, according to his report, found evidence of an ongoing, and unaddressed, rodent infestation. He noted mouse droppings on a kitchen prep table, on shelving, on dishes stored beneath a dishwashing machine, inches away from raw food.

According to Belo, restaurant staff were still not properly washing their hands and he found cooked chicken parts stored in a large open pot on a sidewalk behind the restaurant.

The restaurant voluntarily closed for a day. On April 18, another sanitarian visited for a 50-minute follow-up inspection labeled "special service," wrote "mouse infestation not observed" on a report, and granted Joy Tsin Lau permission to reopen.

Less than two weeks later, the city filed suit.

Speaking about similar suits, Andrew Ross, a chief deputy city solicitor, said judges have granted the city permission to close problem restaurants. But the closures are only temporary.

"We can't lawfully keep someone closed if they demonstrate they're operating within the law," Ross said.

If a restaurant fails to correct problems, the case could be brought to the city's Licenses and Inspection department, which has the power to revoke business licenses. But no case against Joy Tsin Lau has ever gone that far.

215-854-2796 @samwoodiii