The coronavirus was detected Wednesday on a surface sample taken from a batch of chicken wings during screening of imported frozen food in Longgang district of Shenzhen, the municipal government said in a statement. Officials did not name the brand.

Shenzhen health authorities immediately traced and tested people who might have come into contact with the product, and all results came back negative; all related products in stock have been sealed off and tested negative, the statement said.

Authorities are now tracing related products from the same brand that have already been sold, and have disinfected the area where the contaminated chicken wings were stored.

These incidents have sparked concerns over the safety of imported foods. Chinese health authorities have repeatedly told the public to be cautious about buying imported meat and seafood. On Chinese social media, some have called for the suspension of all frozen food imports.

But health authorities, including the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC), have said the possibility of catching the virus through food is low.