BEIJING/SHANGHAI : A sample of frozen chicken wings imported into the southern Chinese city of Shenzhen from Brazil has tested positive for coronavirus, the city government said on Thursday, raising fears that contaminated food shipments could cause new outbreaks.Local disease control centres tested a surface sample taken from the chicken wings as part of routine screenings carried out on meat and seafood imports since June, when a new outbreak in Beijing was linked to the city's Xinfadi wholesale food centre.The discovery came a day after traces of the coronavirus that causes COVID-19 were found on the packaging of frozen shrimp from Ecuador.