Several reports around the world have described coronavirus pathogens on packaged frozen food as a source of infection. Although the World Health Organization said that transmission from food and food packaging is 'highly unlikely,' a recent study from China claims to have found evidence to indicate otherwise.
Researchers from Guangdong Academy of Agricultural Sciences and South China Agricultural University observed that the virus could survive up to eight days on food and packaging stored at 39 degrees Fahrenheit. Fish is typically transported at that temperature, which may explain why some infection cases have been linked to salmon.
With the virus contaminating fish for more than a week, it can easily be the source of international transmissions due to the import and export of salmon and other fish, according to the scientists.
The report also indicated that fish is typically stored and transported in low-temperature environments, unlike vegetables and other food. The virus stays attached to the skin as the fish makes its way to markets and groceries.
Imported Food & Packaging
One of the first cases of coronavirus being associated with fish was in mid-June when traces of the pathogen was found on chopping boards used for imported salmon in Beijing. A young man, who cleaned frozen seafood, tested positive for the virus in the same area.
After further investigations, nearly 150 positive cases were linked to the Xinfadi market, Beijing's largest wholesale market. Other chopping boards that were not used for imported salmon also tested positive for coronavirus.
At the time, the Chinese Centre for Disease Control found no evidence that salmon could host the pathogen. Virologist Cheng Gong also said at the time, 'All known evidence so far suggests this kind of receptors exist only in mammals, not fish.'
Since June, Chinese authorities have been investigating other packaging, containers, and imported meat. The customs agency recently reported that six out of hundreds of thousands of samples tested positive for SARS-CoV-2 pathogens.
Another report weeks ago found traces of the virus on frozen chicken wings that arrived in China from Brazil. A surface sample indicated the pathogen after imported frozen food was screened.
Read Also: Are Food Supplies Still Safe? Coronavirus Outbreaks in Meat Packaging Plants Cause Worldwide Worries
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Frozen Virus
In April, the WHO said that there was no evidence indicating that traces of the virus on food and food packaging was infectious. 'Coronaviruses cannot multiply in food; they need an animal or human host to multiply,' said the organization.
However, according to Benjamin Cowling from the University of Hong Kong, it is known that viruses can survive in frozen environments. Theoretically, the infectious virus could spread this way.
Cowling explained that, in reality, that scenario is low-risk since the virus would have to survive being frozen and defrosting. The virus needs a host to survive, so 'It would need to get onto someone's hands and then into their nose or mouth, and still survive.'
Despite the lack of evidence, Chinese authorities continue to take safety precautions and have suspended imports from several trading partners.
Read Also: Coronavirus May Have Spread to New Zealand Through Frozen Food Packaging, Experts Say
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