A medical staff prepares for the nucleic acid testing at a laboratory of a supervised warehouse for imported cold chain food in Zhengzhou, central China's Henan Province, Jan. 22, 2021. Two supervised warehouses for imported cold chain food have been put into use in Zhengzhou on Jan. 20. All of the imported cold chain food entering Zhengzhou would be tested and disinfected here.Photo:Xinhua

Staff members lie imported food on a disinfection machine at a supervised warehouse for imported cold chain food in Zhengzhou, central China's Henan Province, Jan. 22, 2021. Two supervised warehouses for imported cold chain food have been put into use in Zhengzhou on Jan. 20. All of the imported cold chain food entering Zhengzhou would be tested and disinfected here.Photo:Xinhua

Staff members lie imported food on a disinfection machine at a supervised warehouse for imported cold chain food in Zhengzhou, central China's Henan Province, Jan. 22, 2021. Two supervised warehouses for imported cold chain food have been put into use in Zhengzhou on Jan. 20. All of the imported cold chain food entering Zhengzhou would be tested and disinfected here.Photo:Xinhua

Staff members lie imported food on a disinfection machine at a supervised warehouse for imported cold chain food in Zhengzhou, central China's Henan Province, Jan. 22, 2021. Two supervised warehouses for imported cold chain food have been put into use in Zhengzhou on Jan. 20. All of the imported cold chain food entering Zhengzhou would be tested and disinfected here.Photo:Xinhua

Staff members lie imported food on a disinfection machine at a supervised warehouse for imported cold chain food in Zhengzhou, central China's Henan Province, Jan. 22, 2021. Two supervised warehouses for imported cold chain food have been put into use in Zhengzhou on Jan. 20. All of the imported cold chain food entering Zhengzhou would be tested and disinfected here.Photo:Xinhua