China is zeroing in on cold chain goods to prevent any outbreaks of Covid-19 after packaging of frozen Argentine beef, German pork and Indian cuttlefish tested positive for the virus.
Cities across China, the world’s largest importer of beef and pork, have pledged to strengthen screening and sterilisation of imports.
The latest campaign to safeguard China’s borders against any reintroduction of Covid-19 began after officials in the northeastern city of Tianjin, one of the country’s largest ports, tied an infection of a worker in a warehouse to frozen pork imports from Germany last week.
In the following days, food packaging tested positive for coronavirus in cities ranging from eastern Jining to southern Xiamen and central Zhengzhou.
Shanghai municipal government said it would start testing goods in supermarkets and warehouses as part of emergency measures to ensure the safety of frozen goods. The announcement mentioned beef from Argentina, shrimps from Ecuador and fish from Indonesia as priorities.
Beijing also launched a nationwide effort to disinfect and trace cold chain imports. According to regulations, a single positive Sars-Cov-2 test, the virus that causes Covid-19, can lead to a company’s goods being suspended for a week, while three positive tests can result in a month-long suspension.
Tianjin officials’ claims about the source of infection have been rebuffed in Germany. A spokesperson from Germany’s Ministry for Food and Agriculture told public broadcaster Deutsche Welle that, despite transmission being theoretically possible, there remained “no known cases of infection with Sars-Cov-2 through . . . contact with contaminated meat products or surfaces”.
Siddharth Sridhar, from the University of Hong Kong’s Department of Microbiology, said: “It’s important to keep a sense of perspective. The vast majority of transmission is because of person-to-person infection via transportation in the air.”
He said that there was a theoretical “non-zero” risk of infection from the virus transmitted by cold surfaces but that there had been no clear instances of it spreading that way.
But Chinese public health officials remain adamant that cold chain transport carries serious risks of infection. National leaders have repeatedly warned local officials to be vigilant against the re-emergence of Covid-19, despite the country having largely brought the virus under control since March.
The bid for total eradication has led to a zero-tolerance approach. Small clusters of infections are met with strict lockdowns and citywide testing drives.
While experts continue to debate the necessity of China’s resource-intensive efforts to minimise the risk of outbreaks from frozen foods, some research has supported Beijing’s assertions about transmission risks.
An August paper led by Dale Fisher, an infectious disease expert at Singapore National University, found that frozen food could feasibly cause outbreaks in regions where the disease had been controlled.
The authors of the paper, which has not been peer reviewed, found that Sars-Cov-2 could survive being refrigerated or frozen on cubes of pork, salmon and chicken. They did not carry out the same test for packaging.
“We believe it is possible that contaminated imported food can transfer virus to workers,” the authors wrote. “An infected food handler has the potential to become an index case of a new outbreak.”