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Medicine Science

You Probably Won't Catch the Coronavirus From Frozen Food (nytimes.com) 83

Posted by msmash from the closer-look dept.
Amid a flurry of concern over reports that frozen chicken wings imported to China from Brazil had tested positive for the coronavirus, experts said on Thursday that the likelihood of catching the virus from food -- especially frozen, packaged food -- is exceedingly low. From a report: "This means somebody probably handled those chicken wings who might have had the virus," said Angela Rasmussen, a virologist at Columbia University. "But it doesn't mean, 'Oh my god, nobody buy any chicken wings because they're contaminated.'" Guidelines from the Centers for Disease Control and Prevention maintain that "there is no evidence to suggest that handling food or consuming food is associated with Covid-19." The main route the virus is known to take from person to person is through spray from sneezing, coughing, speaking or even breathing.

"I make no connection between this and any fear that this is the cause of any long-distance transmission events," said C. Brandon Ogbunu, a disease ecologist at Yale University. When the virus crosses international boundaries, it's almost certainly chauffeured by people, rather than the commercial products they ship. The chicken wings were screened on Wednesday in Shenzhen's Longgang district, where officials have been testing imports for the presence of coronavirus genetic material, or RNA. Several samples taken from the outer packaging of frozen seafood, some of which had been shipped in from Ecuador, recently tested positive for virus RNA in China's Anhui, Shaanxi and Shandong provinces as well. Laboratory procedures that search for RNA also form the basis of most of the coronavirus tests performed in people. But RNA is only a proxy for the presence of the virus, which can leave behind bits of its genetic material even after it has been destroyed, Dr. Ogbunu said. "This is just detecting the signature that the virus has been there at some point," he said.
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You Probably Won't Catch the Coronavirus From Frozen Food More

You Probably Won't Catch the Coronavirus From Frozen Food

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  • Well, obviously (Score:5, Funny)

    by Rosco P. Coltrane ( 209368 ) on Saturday August 15, 2020 @03:18AM (#60403309)

    Coronavirus is only transmitted by 5G, nobody sells no frozen 5G.

  • Like X-ray of bones (Score:5, Informative)

    by DrYak ( 748999 ) on Saturday August 15, 2020 @03:21AM (#60403313) Homepage

    A metaphor would be that RT-qPCR is like an X-ray used to look for bones.

    A living, breathing human does have bones. But simply seeing a bone doesn't necessarily mean that the human is living and breathing, nor even that you're actually looking at the bone inside a human and not just some left over bone on a graveyard.
    And you need at least a small army of such living, breathing humans, if you want to be able to successfully invade a small country.

    The RT-qPCR is a good tool to detect bits of RNA, and the SARS-CoV-2 contains RNA genetic material.
    But you can't guarantee:
    - ...that the bit you detected actually came from a virus and not just some left over debris. (Even more so because optimisations: the current PCR test only checks for very small sequence of RNA. It's definitely NOT the 48h-long fully genome assembly - that, e.g., we do at work [github.io]).
    - ...that the virus was still functional and able to infect a cell.
    - ...that you have enough virus particles to be able to successfully infect somebody.

    For the first two you'd need at least some cell cultures to confirm, for the last you would need to perform even more complicated tests (trying to infect some model organism).
    The former is going to be too expensive and cumbersome to be performed en masse, the latter is ethically dubious to sacrifice monkey on an industrial scale just to check the safety of every shipment from a country with active cases such as China, Brazil or the US.

    ---

    Also you're most likely to cook you food.
    And cooking was precisely invented by our million year old Homo Erectus ancestors, because not only does it make the food more digestible, but also because it sterilizes it.
    So the whole point of checking food product for virus RNA is moot.

  • If you buy chickens from here, no Brazil Covid for you! And domestic food is only handled by US Americans who ... oh ...

    Well, I guess you're fucked, America.

  • If it IS live virus it will last a LONG time froze (Score:5, Informative)

    by Ungrounded Lightning ( 62228 ) on Saturday August 15, 2020 @04:11AM (#60403363) Journal

    "there is no evidence to suggest that handling food or consuming food is associated with Covid-19."

    Weasel-wording. Absence of evidence is NOT evidence of absence.

    We've seen this formulation a lot with SARS-CoV-2, from officials telling us some behavior is probably safe, only to find out months later that it's not - it's just not so glaringly obvious that they'd isolated it from other transmission methods and SHOWN that it happens. (For instance, they're still telling us that it's just droplets, not aerosols, so within 6 feet (rather than 20 feet, or in-the-same-HVAC-air-circulation-zone, or, say, several miles outdoors in a mild breeze) is a risk.)

    If SARS-CoV-2 is like other coronaviruses, it could easily survive just fine for more than two YEARS frozen. If so, and it's on the OUTSIDE of a frozen food package (e.g. from handling during shipping and processing), it's not going to die off while the package is in the freezer for the ordinary life of frozen food (and will also contaminate the freezer and the rest of its contents). Handle the stuff months later, touch your mouth or eye, and you might become a statistic.

    Now if you get the outside of the package cleaned, and it's a frozen entre' or uncooked chicken parts, IMHO you should be fine even if the inside got contaminated. A frozen entre' will be heated, untouched, before eating, and that will kill the coronairus. So just wash, untouched, anything you used to poke a steam hole in the package, and wash your hands after handling the uncooked inner package (using a different knuckle or finger to close the nuke's door and push it's buttons). The precautions you take with raw chicken to avoid salmonella should also protect you from coronavirus. which is more fragile. (Treat raw pork, raw beef, or other raw or cooked frozen components like raw chicken and you're fine.)

    When I get frozen food I handle it with gloves keep it wrapped until I get it home, then (before it accumulates condensation) clean the outide of the package by rubbing it thoroughly with a pad of paper towel soaked in rubbing alcohol. 91% if I have it. If not, 70% and LOTS of care to prevent dilution to below 70ish by condensation or ice on the packages. (Keep the packages dry and refresh the alcohol or use a new pad for each package.) Then into the freezer. (We've been sequestered almost four months and haven't gotten COVID-19 yet, cross fingers...)

    • (We've been sequestered almost four months and haven't gotten COVID-19 yet, cross fingers...)

      Wife (a food science graduate) agrees wholeheartedly with my previous post, but points out it's a bit over 5 months we've been sequestered. (Since March 10.)

      How the time flies when you're stayin' alive, stayin' alive...

    • Re: (Score:2)

      by gweihir ( 88907 )

      Talk about overdoing it. After handling frozen food, especially chicken, (whether packaged or not) you should wash your hands anyways. And the food itself should be thoroughly cooked. That is designed to kill salmonella and will nicely eliminate Covid-19 as well.

      • When the shrimp packing plant of my preferred brand had an outbreak, I didn't stop buying it. I just make extra-sure I follow safe handling practices. When I take it out of the freezer, I make sure not to touch anything else, and then I wash my hands. Easy. Just make sure you really do what you were already supposed to do, and the food is already safe. Amazing how that works!

        The only restaurant in town that had an outbreak is the place I had already nicknamed "Zombie BBQ" because they had a giant crowd of u

        • Every restaurant has people handling the food. Every restaurant has customers touching surfaces right before eating. Not every customer washes their hands after touching the front door; in fact, there aren't really enough restrooms to make that likely. People touch surfaces in the grocery store all day. None of these situations is causing outbreaks.

          ORLY? And how do you know that?

          So what if the route is rare? It doesn't make the disease any less dangerous if you get it that way - or airborne from someone w

    • Weasel-wording. Absence of evidence is NOT evidence of absence.

      No. It's that evidence of absence cannot exist, even if "absence" is the true state of affairs. The way to study this problem would be to cough on a thousand pizzas, freeze them, then check them for presence of the virus. If none of them have the virus, you have "absence of evidence that the virus survives freezing". It's not weasel-wording, it's them being honest.

    • Good post. Two tweaks from studies:

      1. 160*F for 26 minutes is the energy/effectiveness maximum for denaturing 5-9's of nCoV-19.

      There are ACE-2 receptors in the gut but probably not enough viral load with cooked food to cause any disease. Low-level variolation may be beneficial.

      2. 91% isopropanol is less effective than 70%. Water as a solvent has synergistic effects down to 65%.

      Save money and dilute your 91%. Sometimes 91% is the cheapest way to buy, other times it's selling at a premium due to market shor

      • Re:If it IS live virus it will last a LONG time fr (Score:4, Interesting)

        by Ungrounded Lightning ( 62228 ) on Saturday August 15, 2020 @08:35AM (#60403761) Journal

        91% isopropanol is less effective than 70%. Water as a solvent has synergistic effects down to 65%

        But only slightly less. (As I understand it effectiveness starts falling off rapidly both above 91% and below 70%)

        70% and 91% isopropanol are the stock strengths you find in stores. You miss the point of going with the high strength when doing frozen food. The package will have some condensation and/or frost on the surface. The alcohol will act as antifreeze, thawing it. Then the thawed ice will dilute the alcohol.

        Use 91% and the sanitizing solution starts out good and gets better, not coming back to where it started until it's soaked up enough water to start pulling it below 70%. That means it can grab about a fifth of its own volume of water before it starts to become ineffective.

        Start out at 70% and you'd better not have any substantial amount of frost or condensation at all, because diluting the alcohol only a little brings the mix below 70%, which is the minimum recommended for killing off the virus. You need essentially frost free packages and a lot of rubbing alcohol to be safe.

        • But only slightly less. (As I understand it effectiveness starts falling off rapidly both above 91% and below 70%) ...
          Start out at 70% and you'd better not have any substantial amount of frost or condensation at all, because diluting the alcohol only a little brings the mix below 70%, which is the minimum recommended for killing off the virus. You need essentially frost free packages and a lot of rubbing alcohol to be safe.

          Correction: CDC says down to 60% is OK. So a 70% solution can take a little bit of

    • Absence of evidence is NOT evidence of absence.

      Indeed, if you have a large enough sample size it only becomes strongly suggestive, rather than "evidence" of what happened.

      The data strongly suggests that handling food or consuming food is not associated with Covid-19.

    • Re: (Score:3)

      by hey! ( 33014 )

      Here we actually have pretty good evidence that SARS-CoV-2 doesn't survive well on freezing: large samples of frozen food that were definitely contaminated (we can find the viral RNA), but from which no viable virus can be recovered.

      Viral survival follows an exponential decay curve, so it's always possible that you might get a piece of food that's on the unlucky tail of the curve. But from a health perspective you have to ask, is it a *practical* risk?

      We live in a world full of risks, and in general when a

    • Re: (Score:2)

      by jma05 ( 897351 )

      That's not weasel-wording. It means exactly what it says.

  • Too little meat.

    And breast too.

    Too dry.

    That's why we send them over to the US. ;)

  • Over whatever the fuck the USA is doing: https://www.bloomberg.com/opin... [bloomberg.com]

  • First: it is unlikely that enough viruses survive freezing that an infection is even remotely possible.
    Secondly: the only food you eat frozen is "ice cream". Every frozen food, you most likely heat to "close to boiling" after thawing it: and that definitely does not survive any virus.
    Thirdly: digesting a virus, most likely has no chance at all to infect you anyway ...

    So the only remotely possible infection way is: a virus survived thawing and you touch your face during preparing the food and infect you that

  • ...and the chicken industry chickens out.

  • New Zealand (Score:4, Insightful)

    by cirby ( 2599 ) on Saturday August 15, 2020 @05:15AM (#60403449)

    This little urban legend got a big boost because some people in New Zealand got sick, and one of them worked at a frozen food storage center that had some products from China.

    They assumed that it had to be from the frozen products, because they were holding on to the fantasy that the New Zealand shutdown was 100% perfect, and nobody managed to sneak past their border shutdown. Despite, of course, knowing that a ship actually delivered those products, and ships have people on them...

    • Re: (Score:2)

      by rldp ( 6381096 )

      What about widely spread reports that it can live on a cold metal surface for days at a time?

      Incite panic you get panic

      • What about widely spread reports that it can live on a cold metal surface for days at a time?

        Those are mostly mischaracterizations by media idiots, repeated uncritically by people like you.

        What they actually reported was that they found genetic material from the virus in the sample even after it was frozen. That doesn't mean they found the virus.

        Consider this: You sit in a chair for most of the day. Then you stand up, and go home. I come in and take the chair. I test the chair for your DNA. I find your DNA on the chair. Did I find evidence that you are in the chair? No! I did not. I place the chair

    • Re: (Score:1)

      by atuwh ( 1245444 )
      There's a few interesting points here though:
      • - The current cluster can't be traced back anything earlier than the frozen food storage center. This is despite extensive testing and contact tracing (yesterday there were 24K tests with 7 positive results [health.govt.nz]).
      • - Genomic testing can't connect the current outbreak with the first outbreak here from three months (or so) back or with current cases caught at the border - it's new to New Zealand.
      • - The virus could have come from people on ships, true, but it's qui

    • Re: (Score:2)

      by jrumney ( 197329 )

      "From China" has never factored into the New Zealand case. It is a red herring, this virus is more prevalent in North and South America, South Africa, India and Europe than in China. There is no need to throw that casual racism in there.

      They are investigating the possibility of importation on the packaging of frozen products and being kept active longer than usual by the cold temperatures, as the virus RNA of the latest cases does not match that of any previous known cases in NZ. They are also investigat

  • No corona, frozona (Score:3)

    by AndyKron ( 937105 ) on Saturday August 15, 2020 @05:31AM (#60403461)
    Of course not. You catch frozavirus from that.
  • Explain like I'm five how an infectious coronavirus carrier, sneezing or coughing onto raw meat that is then placed in a cold-store, would not contaminate the meat.
    • Um...let's see...
      1. you're supposed to wash your hands after handling raw meat
      2. You're supposed to cook your meat at high temperature before consuming it
      3. Presumably the virus can't infect dead meat, so it's not like it's going to be any different from sneezing onto an inanimate surface
      4. CDC said they couldn't culture thr virus left out on surfaces after a day or so, so if the meat takes longer than that to ship, it'll be fine on the other side
      But yeah: No data on how cold you can freeze the virus to pre
  • "Denatured" and frequently is used to describe what happens to organic molecules, especially large proteins, outside of their nominal operating temperature or pH range.
  • To preserve virusses, they are put in a freezer. That's the way researchers store it. And China clearly indicated this as the path of a major reinfection. New Zealand might come to the same conclusion, it might not be, we will probably know soon. Most people wash their hands prior to preparing their food, not after handling frozen food. With proper precautions the chance to contaminate that side salad might reduce significantly. And the packaging of frozen food can be decontaminated too. Ignoring the proble
  • If you don't wash your hands after handling raw meat, and if you don't cook raw meat before consuming it you probably already have worse problems than COVID-19. Salmonella for instance.

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