Coronavirus was found on ice cream produced in eastern China, prompting a recall of cartons from the same batch, according to the government.
The Daqiaodao Food Co in Tianjin, adjacent to Beijing, was sealed and its employees were being tested for Covid-19, a city government statement said.
There was no indication anyone had contracted the virus from the ice cream.
It said 390 sold in Tianjin were being tracked down and authorities elsewhere were notified of sales to their areas.
The ingredients included New Zealand milk powder and whey powder from Ukraine, the government said.
The Chinese government has suggested the disease, first detected in the central city of Wuhan in late 2019, came from abroad and has highlighted what it says are discoveries of the coronavirus on imported fish and other food, though foreign scientists are sceptical.