Medical staff collect samples for the nucleic acid testing of imported food packages 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. (Xinhua/Li Jianan)
