Health authorities in the Chinese capital on Sunday issued guidelines on the self-protection of workers in the cold-chain food industry after a number of new COVID-19 cases were related to exposure to imported frozen foods.

The guidelines asked workers to wear facial masks and disposable gloves when handling frozen foods and to disinfect their uniforms when necessary, Beijing's center for disease control and prevention said at a press conference.

Workers loading and unloading such goods are also advised to wear goggles and face shields if needs arise, and avoid frequent contact between their skin and goods, according to the guidelines.

Pang Xinghuo, deputy director of the center, said at the conference that new COVID-19 cases were reported from employees of the cold-chain industry in many places in China, as the COVID-19 pandemic continues to rage overseas.

China has stepped up efforts to block COVID-19 through imported food. The Ministry of Transport released a guideline in mid-November to prevent the transmission of the novel coronavirus through cold-chain foods imported via road and waterways.

Local authorities in north China's Tianjin Municipality said on Sunday that samples collected from the packaging of a batch of imported frozen pork tested positive for COVID-19, the latest in a series of reports on the virus found on imported frozen foods.