Some environmental samples of a banana wholesale market and a fruit storage area tested positive for coronavirus, though the city reported zero new local COVID-19 cases on Wednesday.

Liu Xiaofeng, deputy director of the Beijing Center for Disease Prevention and Control, said at a Thursday news conference the two districts - Tongzhou and Shunyi — where the positive samples were found have conducted swift investigations to trace people and items at risk of infection.

He also reminded the public to purchase fruit, vegetables and cold-chain food at supermarkets following proper protocols.

According to Dong Minghui, deputy head of Tongzhou district, the authority has collected 8,761 environmental samples in the banana wholesale market on Wednesday and 57 tested positive.

The whole market has been disinfected, an area of 80,000 square meters. Twenty-three close contacts and 15 people at high risk have been quarantined.

The storage facility in Shunyi, where the batch of bananas with positive results was stored, had 2,850 spots tested and 40 positive samples.

The authority has administered nucleic acid tests to all people involved and is waiting for the results.