No meat or seafood products that were imported following the latest cluster of COVID-19 infections in Beijing have been found with the novel coronavirus, a customs official said on Friday, adding that the customs authority will continue strict inspection and quarantine measures to ensure the safety of imported food.

Despite "extremely low" risks of coronavirus spread via the food trade, since February the General Administration of Customs has directed some of its branches to inspect for the virus while ensuring normal trade, said Song Yueqian, deputy head of the administration's health and quarantine department.

So far, all tests on imported goods have been negative, he said at a news conference.

After the recent cluster outbreak of COVID-19 in Beijing, which many people believe could be linked with imported salmon sold at a wholesale market in the capital, customs across China have intensified inspection and coronavirus tests over food in the cold chain, such as seafood products, meat and frozen vegetables, that were imported from countries and regions with high risks of the epidemic, Song said.

On Thursday alone, customs across China inspected more than 15,600 samples, including more than 3,500 goods and more than 10,600 packages. So far, none have tested positive, he said.

The latest COVID-19 outbreak in Beijing has been linked with Xinfadi, the biggest wholesale market for agricultural and seafood products in Beijing. A number of samples collected from the market, including cutting boards for salmon, tested positive for the virus, Beijing's health authority said, although efforts are still underway to determine the source of the virus.

Feng Luzhao, a researcher of infectious diseases at the Chinese Center for Disease Control and Prevention, said the study shows that the primary ways for transmission of the coronavirus are respiratory droplets and physical contact, and there is no clear evidence yet that it can spread through food.

"But we suggest people be cautious with food safety and practice hygiene when cleaning, cooking and eating food, including avoiding touching raw fish and meat directly and only eating fully cooked food," he said.

To aid proper resumption of work and production while carrying out COVID-19 epidemic prevention and control across China, the National Health Commission released a guideline on Thursday eyeing key venues and key groups of people.

It included guidance on using masks on different occasions by the public, using ventilation facilities properly and epidemic measures to be taken in higher-risk places such as theaters, hospitals and public transportation.