On November 8, a cold storage worker in Tianjin, north China, was confirmed to have the novel coronavirus disease (COVID-19) and the virus was also detected on a door handle of the storage.

Moreover, there were reports from the cities of Dezhou in east China and Taiyuan in the north that the outer packagings of imported frozen food sent from Tianjin were also detected to have the virus on November 7.

Tianjin has responded promptly, sealing the cold storage and testing people and the surrounding areas.

With regular prevention and control measures followed, governments at all levels have shown commendable performance in reining in sporadic outbreaks in Qingdao, Shandong Province in east China, and Dalian, Liaoning Province in northeast China. However, the packaging of imported food showing the presence of the virus means the problem remains.

Since July, there were several cases of the virus being found on the packaging of frozen food. However, if environmental monitoring can be done, even that can be controlled.

Environmental monitoring checks the quality of an area's environment with various data obtained through chemical, physical, biological, medical and other means. It can be used to track pollution sources and provides a basis for management and control of pollution. The imported frozen food contaminations indicate links such as transportation and storage need enhanced environmental monitoring.

On October 26, the State Council released two guidelines for a COVID-19 prevention and control mechanism, saying a health registration system should be established for employees of cold chain companies. Also, disinfection of food packages imported from high-risk regions and countries should be enhanced.

The chain of imported frozen food consists of production, process, packaging, storage, transportation and sales. So the concerned authorities and companies have been asked to pay more attention to environmental monitoring in warehouses, vehicles and other applicable places.