ZHENGZHOU -- Yuanyang County in Central China's Henan province has found that an imported frozen food packaging sample tested positive for the novel coronavirus.

The sample was taken from the packaging of a batch of imported frozen shrimp from South America, local authorities in Yuanyang reported late Sunday.

As of Monday morning, local authorities have conducted nucleic acid tests on 22 relevant people, including those who had direct contact with the food. All results showed negative.

Authorities have also sealed the shipment of frozen food from which the tainted sample was taken and disinfected the storage facility.

The tainted sample in Yuanyang County was from the same shipment of imported frozen shrimp where coronavirus had been found days ago in Zhengzhou, the provincial capital.