Chicken wings with traces of COVID reignite questions about food-borne transmission risks
Officials in China’s southern metropolis Shenzhen reported Thursday they had found traces of COVID-19 on a batch of chicken wings imported from South America. Media reports soon claimed chicken wings had “tested positive” for coronavirus, stoking fears the virus has found its way into the world’s food supply. The World Health Organization says, however, that’s not a concern.
“We have no examples of where this virus has been transmitted as a food-borne [disease], where someone has consumed a food product [and become infected],” WHO head of emerging diseases unit Maria van Kerkhove said during a regular press briefing Thursday.
Although COVID-19 is a zoonotic virus, meaning it originated in an animal before transferring to humans, it likely didn’t do so through consumption. As Van Kerkhove points out, if the virus was in our meat supply it would be killed when the meat is cooked. Raw food, like sushi or even runny eggs, poses more of a risk, but so far the virus has not been found inside those products.
The original outbreak of COVID-19 at a market in Wuhan more likely occurred because humans had close contact with both live and dead animals and didn’t take proper hygiene precautions, such as washing their hands.
Still, a recent flurry of incidents connecting coronavirus outbreaks with food markets has caused concern. In June Beijing shut down a seafood market after a cluster of COVID-19 cases were traced to one of the stalls there. Officials speculated the virus had been imported along with fish from Europe, prompting a sudden boycott of Norwegian salmon.
This week, New Zealand reinstated a nationwide lockdown after a COVID-19 cluster emerged in Auckland. The island country had gone 102 days without a single local transmission case before the cluster emerged. Local authorities are investigating whether the virus could have been imported along with frozen food since one of the patients worked at a cold storage unit.
Chinese officials also suspended meat imports from three Ecuadorean companies this week after COVID-19 was found on packages of frozen prawns. Samples taken from inside the packages and from the prawns themselves tested negative for coronavirus.
“The results show that the container and the packaging of these companies are under the risk of becoming contaminated by the novel coronavirus. Experts said that while this does not mean they can transmit the virus, it shows that the management of food safety is not ideal,” Bi Kexin, director general of China’s Import and Export Food Safety Bureau, said about the suspect prawn imports.
In the case of the Shenzhen chicken wings, too, COVID-19 was found only on the surface of the chicken and the packaging of the meat—not inside the chicken itself. The COVID-19 virus can stay alive on any surface for a period of time, including on plastic food packaging. Professor Leo Poon at Hong Kong University says that at room temperature the virus can survive on a surface for several days, but at 4 C (39.2 F) it can last up to two weeks. “Below freezing, it could survive even longer than that,” Poon says.
The potential for COVID-19 to be transported worldwide through refrigerated shipping units could complicate virus containment measures, but the theory has yet to be confirmed. According to Bi, Beijing has turned up only six positive COVID-19 samples from close to 223,000 taken from frozen imports. Workers handling the food shipments face risks, but Van Kerkhove says the WHO has issued guidance on how “people handling these products can work safely,” such as by washing their hands.
In China, health authorities are advising consumers to take extra precautions while purchasing frozen imports, but WHO Health Emergencies Programme executive director Michael Ryan advocates calm.
“People should not fear food or food packaging,” Ryan says. “We will continue to track findings like this but…there is no evidence that the food chain is participating in the transmission of this virus.”