Frozen fish Photo: Xinhua

Against the backdrop of emerging imported cases of the novel coronavirus detected in non-cold chain products, China's top epidemiologist has called for the current sampling and testing goods and regular personnel screening on cold chain to be adopted on non-cold chain items in a bid to prevent the potential risk of a resurgence in cases during winter time.

Meanwhile, the country's top medical adviser has also called for a circuit breaker mechanism for frozen food imports and suspend imports of certain products from countries and regions if the virus were found on the products.

After beginning winter, all international freight environments are similar to the cold chain in summer, said Wu Zunyou, chief epidemiologist at the Chinese Center for Disease Control and Prevention on Saturday, indicating that the low temperatures in winter cause the non-cold chain environment to experience the cold chain effect when it comes to the potential risks of carrying the novel coronavirus in restoration and distribution.

"Low temperatures in winter can prolong the survival time of the virus on the surface of containers, and increase the risk of infection when it comes into contact with items in the frozen environment," said Wu, noting that in many places, imported non-cold-chain items have also caused human infection.

This remark came after one of the two newly-confirmed COVID-19 cases in Shanghai on Friday was found to be a porter at the cargo terminal in Pudong Airport. Different from previous confirmed cases which were all related to imported cold-chain items, the recent case suggests that the person had only contact history in his daily work that related to imported non-cold chain items, raising new questions over whether the novel coronavirus may also be imported through non-cold chain, the Paper  reported on Saturday.

The recent severe international epidemic has increased the risk of contamination of overseas goods, said Wu in a media report, responding to the recent case in Shanghai.

Due to the increasingly severe pandemic abroad, China should also establish a circuit breaker mechanism for frozen food imports and suspend product imports for two months from countries and regions where the virus was found in imported goods, said China's top medical adviser Zhang Boli in a media interview, Tianjin Daily reported.

The pandemic abroad is getting more serious and asymptomatic infections are on the rise. Coupled with the winter and colder weather, the novel coronavirus lives longer on the contaminated surface, said Zhang, noting that therefore, in addition to preventing entry personnel, it is also necessary to prevent imported goods from carrying viruses.

On Saturday, China reported 17 new confirmed cases, including 14 imported cases from overseas.

Zhang Wenhong, a leading infectious disease specialist, noted at a press conference on Saturday that the local cases show there is risk of COVID-19 outbreaks during the coming winter and spring.

At present, many domestic enterprises have strengthened environmental detection and personnel screening, and the infection can be detected in a timely manner, experts said.