Is the corona virus in our freezer? – Science

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China is increasingly convinced that the coronavirus can survive in frozen food. Is SARS-CoV-2 after airborne, now as well foodborne?

In June, a huge wholesale market in south Beijing was found to be the source of a wave of new infections from imported frozen salmon. It was an old variant of a European strain of the corona virus. Although the virus may have been present on the Xinfadi market for some time and could survive in a dark and humid environment, the hypothesis that it came to China from Europe via frozen food is gaining more and more support.

In June, a huge wholesale market in south Beijing was found to be the source of a wave of new infections from imported frozen salmon. It was an old variant of a European strain of the corona virus. Although the virus may have been present on the Xinfadi market for some time and could survive in a dark and humid environment, the hypothesis that it came to China from Europe via frozen food is gaining more and more support. This is because in recent weeks the virus has also increasingly been found in and on packaging of frozen food. This was the case for frozen shrimp from Ecuador and frozen chicken wings from Brazil. The new wave in New Zealand could also be traced back to a factory where imported frozen food is processed. The Chinese government is warning its population against the consumption of imported frozen products. Beijing has also banned foreign producers who have come into contact with the virus, such as the American poultry company Tyson Foods and the German meat company Tönnies. It is not the case that the shrimps and chickens themselves can contract the disease. After all, fish, birds, pigs and cattle are not susceptible to SARS-CoV-2. Only minks can get the virus and pass it on to humans. The virus may have reached the packaging of the frozen fish and meat products because someone who was infected has touched them during processing or transport. In principle, this could also be done with fruit and vegetables, but the chance is much smaller because these foods are not processed in cooled, damp areas such as slaughterhouses and fish farms, where the virus thrives. SARS-CoV-2 survives on surfaces such as cardboard (1 day) and plastic (3 days). In addition, it is resistant to the cold, and perhaps even better to freezing temperatures. Previous studies have shown that other members of the coronavirus family normally survive for two years in the freezer. SARS (SARS-CoV) and MERS (MERS-CoV), also two coronaviruses, last 72 hours in a refrigerator. There is no reason to believe that SARS-CoV-2 would show other properties. That’s why, according to virologists, it’s not a good idea to keep a mouth mask in the freezer, for example, under the assumption that it would kill the virus. On the contrary. But just because the viruses survive at -20 ° C doesn’t mean they can make you sick. A virus needs a living host to multiply and remain infectious. When rna molecules are detected somewhere, it does not mean that the virus is contagious. Rna is the genetic material of a virus, similar to our DNA, which can remain even if the virus itself has been destroyed for a long time. It means the virus has stopped by somewhere and left a souvenir. RNA is also the cause of false positive corona tests in cured patients and so-called ‘second infections’. But to really prove unequivocally that frozen food SARS-CoV-2 is contagious or not, scientists need to isolate the virus from its packaging and demonstrate through animal testing in a lab that the virus can still multiply. These experiments have not yet been performed to this day. In theory, you could get infected by frozen products, but then all the puzzle pieces must fit together very well. The virus must first survive its overseas adventure and subsequent thawing process, it must then still be infectious and not weakened by the dry conditions and lack of a living host, then it must find its way to someone’s hands that are or touch her nose or mouth. In addition, frozen meat or fish is heated during consumption. And the corona virus is certainly not resistant to that. It is recommended to heat food to 70 ° C. The coronavirus is a so-called enveloped virus. It has a fragile jacket that is vulnerable to all kinds of environmental factors such as rapid temperature changes. In the meantime, the World Health Organization (WHO) maintains that the chance that you will become ill from the new coronavirus through (frozen) food or its packaging is ‘highly unlikely’. The food chain is not the driving force behind this pandemic. “China has tested nearly 100,000 packages and less than ten of them prove positive,” the WHO said this week. The coronavirus may be airborne, but it is not foodborne, according to the health organization. The gastrointestinal tract is not the primary route for the virus to spread. That road still runs from person to person through direct coughing, sneezing, speaking or even breathing. Surface transmission is possible when someone touches a surface that an infected person has recently coughed or sneezed on and then brings their hand to their nose or mouth. It is therefore important to always wash your hands properly, even when you come into contact with food. But that advice also applies in non-corona times.

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