Risk of COVID-19 spread via food imports need global attention

By Rahul Vaimal, Associate Editor
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According to a scientist who has studied the phenomenon, there is a serious risk of cross-border coronavirus transmission through the $1.5 trillion global agri-food market.

Contaminated food imports may be able to transfer the virus to both workers and the environment, said Dale Fisher, an infectious disease physician at the National University Hospital in Singapore. In the first part of the transmission chain, frozen-food markets are thought to be an important harbor, he said.

“It’s hitching a ride on the food, infecting the first person that opens the box. It’s not to be confused with supermarket shelves getting infected. It’s really at the marketplace, before there’s been a lot of dilution,” Mr. Fisher, who also chairs the Global Outbreak Alert and Response Network, said.

China’s warnings

In recent months China has been vocal about finding traces of the SARS-CoV-2 (COVID-19 causing virus) pathogen on packaging and food, raising fears that imported items are linked to recent virus resurgences. The Asian country has ordered a range of precautionary steps, creating major disruptions with its trading partners.

Although such transmission continues to be a ‘freakish’ occurrence, the scale of global food exchange is such that it will occur a few times out of millions of imports and exports, Mr. Fisher said.

Ignored by global agencies

This is a theory that the World Health Organization (WHO) and some western nations have downplayed. Recent epidemiological evidence suggests that it is ‘unlikely’ that the virus could be transmitted from surfaces to human respiratory systems, the WHO has said, while the US Food and Drug Administration (FDA) has also confirmed that it is not aware of any evidence to indicate that the disease will spread through food.

The theory is rarely mentioned or debated outside of China, where officials are increasingly weighing in on the idea that the virus may be carried and transmitted via food packaging. Mr. Fisher is one of the few international experts researching the possibility of outbreaks in fresh and frozen food that is contaminated.

“There’s two schools of thought and the minority view which I adhere to is that there’s a lot of circumstantial evidence. A lot of people may be against this because they don’t want to scare the world but the food could be a source,” said Mr. Fisher.

Favorable environment

In the time and temperatures associated with transportation and storage conditions used in the international food trade, experiments performed by the Fisher team indicate that the coronavirus could thrive. The study published in August showed no weakening of the infectious virus even after 21 days when the pathogen was added to chicken, salmon and pork samples at normal food refrigeration and freezing temperatures.

In cold and dry conditions, the fact that the virus appears to flourish has made cold-storage facilities perfect spaces for the spread of the pathogen. Meatpacking plants and factory farms are more likely to be hot spots for COVID-19 outbreaks, more than schools and churches, according to Mr. Fisher.

“It’s because there’s a lot of stainless steel, which it grows on,” he said. “It’s cold, it’s crowded, it’s noisy so the people have to yell.”

Warning bells

Authorities in the eastern Chinese coastal city of Qingdao announced earlier this month that they found live SARS-CoV-2 on imported frozen seafood, with two port staff responsible for the refrigerated packaging unloading testing positive for the virus.

In recent months, China has said several times that imported refrigerated products pose a risk of re-introducing the coronavirus into the country. Following positive tests on shipping containers and food packaging, it subsequently banned imported goods, including seafood from Indonesia and chicken wings from Brazil.

When the virus was tracked to the chopping board of a seller of imported fish, a June outbreak in Beijing caused a nationwide salmon boycott. Also, New Zealand, which has sustained long virus-free periods, said it was looking at the possibility that one of its new clusters could be related to a cold-storage facility.

Mr. Fisher claims that, unlike those in the west now fighting a second wave of diseases, the reason Asian countries are more likely to find proof of food and packaging transmission is due to the now-contained nature of outbreaks in many of its countries.

“You’d never pick it up in the US or in Europe, because you only pick it up if you go from zero cases for 100 days, and then have a small cluster,” he said. “You say, well how did this small cluster start?”

To prevent this, food production companies need to ensure workers are vigilant on mask-wearing, hand-washing and regular sanitization of surfaces and utensils. “And you need to make sure that all these outbreaks in meat processing plants stop,” he concluded.