Current info on COVID and food safety
July 17, 2020 12:54 PM   Subscribe

Is there any better information on COVID and food than what WHO has? I am not super trusting of the CDC right now because I fear their answers are going to be more politically inspired. My question is about food and food packages brought into the house through delivery, not eating in restaurants. The WHO page does not fill me with confidence. More inside.

WHO says there is no evidence that people can get COVID from food or food packaging. However, their answer to the question, "Can the virus live on the surface of food?" is "Coronaviruses cannot multiply in food." You may notice that is not an answer to that question. Or maybe it is, and I don't see it because I don't understand viruses. Please enlighten me if that is the case.

So as we all know absence of evidence is not evidence of absence. How much are people actually looking for evidence of transmission through food? Is there really a way to figure this out? I know that at the beginning of this, there was a lot of panic-inducing information that food safety experts seemed to think was incorrect. I just feel I haven't seen anything that amounts to a concrete answer. And if there isn't one, that's fine. What bugs me is whether we are being told it's safe when no one really knows. I am immunocompromised, if that matters.

(I am looking for info from experts, not how individuals clean their food and food packaging.)

Thank you.
posted by FencingGal to Food & Drink (15 answers total) 8 users marked this as a favorite
 
Best answer: In this Twitter thread by Dr. Bob Wachter, Chair of the UCSF Department of Medicine, he discusses the latest UCSF Grand Rounds COVID update.

The 12th tweet in the thread seems relevant to your question about packaging and surfaces:
12/ @ 1:21:45, re: fomites (surfaces), all 3 speakers agreed that, while it was a major concern in Feb-March (Gandhi: “we didn’t know what was going on”), today, says Edmond, “I worry less about it.” But, though less concerned, all of them do clean their hands pretty regularly.
Here's a video of the full Grand Rounds discussion: Covid-19: How the Virus Gets in and How to Block It: Aerosols, Droplets, Masks, Face Shields, & More
posted by Lexica at 1:04 PM on July 17, 2020 [6 favorites]


Best answer: I think the closest you're going to find is regarding surface transmission in general, such as:
Lancet, July 3: "A clinically significant risk of severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) transmission
by fomites (inanimate surfaces or objects) has been
assumed on the basis of studies that have little
resemblance to real-life scenarios
."

European CDC, last updated July 16: "Indirect transmission through fomites that have been contaminated by respiratory secretions is considered possible, although, so far, transmission through fomites has not been documented." That article goes on to discuss the role that length of exposure seems to play (quoting in particular a high transmission rate through a 9th floor call center in Korea, with otherwise low infection rates throughout the rest of the building), which may be why surface transmission seems insignificant in studies so far: prolonged contact with a surface in which you would continually be accumulating viral exposure is pretty difficult to do, unless you were rubbing your hands all over a table someone was continually licking. One pizza with some virus on it will not grow more virus, so you would need to consume quite a bit of virus pizza to reach the viral load that appears to be from what we know so far sufficient to get sick.

But there is SO MUCH we don't know, you're absolutely right there's no proof. All we really have is Asian contact-tracing data, the more reliable of which is only the Korean data.
posted by Lyn Never at 1:12 PM on July 17, 2020 [6 favorites]


Best answer: Unfortunately, no one is going to be able to give you real answers on this. I know it feels like forever but there just has not been time to do any real studies that tell you what you want to know, which is whether A) there's any virus or B) the virus that's there is still infectious. The first SARS virus (which was a closely related coronavirus, though obviously not as contagious) is killed very quickly by heat. At 56C / 132F (roughly the temperature of a medium steak or a rice cooker) it's 99.99% gone within 15 minutes. It does not appear, however, to be significantly affected by cold. But that's SARS 1.

The kinds of studies that have been done so far on SARS-CoV-2 (which is the term I recommend you Google for if you're looking for science) have not been the slow studies where they test various exposures and then culture them. The studies have basically been DNA tests to see if any virus RNA is still present. If the RNA is gone, obviously the virus is inactive, so that's why you see the studies about so many days on cardboard, steel, copper, etc. However, there's presumably a large interval where the virus is at least partially intact but not active for the purposes of infection. I asked previously if there were any documented cases of fomite / smear transmission and it appears they are unlikely, to put it mildly. But the short answer is that no one has really had the time to assess this particular risk.
posted by wnissen at 1:19 PM on July 17, 2020


Best answer: I think what's important here is how the virus actually gets into our system. Even though it seems like eating a bunch of food that has some virus on it would be dangerous, it's not really an ideal pathway for the virus to get to where it wants to go. Also, as Lyn Never mentioned above, the fact that coronaviruses don't multiply on food is important because you need to have a suitable viral load to even get sick (same reason why fomites aren't primary means of transmission either). Here's what the British Columbia CDC has to say about food safety:

The virus is not believed to be transmitted by eating food because it is destroyed during digestion by the acids in your stomach. The greater risk is getting the virus on your hands and then touching your eyes, nose or mouth. There are no special precautions needed when storing food, but we recommend washing your hands after putting away food you have purchased and before preparing food.
posted by thebots at 1:20 PM on July 17, 2020 [10 favorites]


The greater risk is getting the virus on your hands and then touching your eyes, nose or mouth

This is the part I find confusing- I can see why eating something with the virus might not be bad if it goes to your stomach, but if we're not supposed to touch our mouths, why is it okay to put hypothetical virus-covered food in our mouths?
posted by pinochiette at 1:55 PM on July 17, 2020 [5 favorites]


Best answer: why is it okay to put hypothetical virus-covered food in our mouths

It's not that it is "okay" or zero risk, but that food-borne transmission is considered a much lower risk. Transmission occurs mostly through respiratory droplets. There is cell culture research from the Netherlands that suggests the SARS-CoV-2 virus can infect a person via the cells in the intestines, and some evidence from virus shed in fecal PCR studies done in China and Europe, but it is a numbers game: enough virus must first clear the harsh acidic environment of the stomach to get there.

It is apparently easier for the virus to infect by breathing it in, and it is easier to control that vector of spread by basic health measures, like having everyone wear masks, check for symptoms, cover food after it is made and before having it delivered, washing hands frequently, etc.

You have to decide how much risk you're comfortable with, based on your lived experience and overall health. Someone who is immunocompromised has to perhaps consider narrowing their scope of what they can accept. We still don't know much about the virus, but we learn more every day as we get closer to treatments and vaccines.
posted by They sucked his brains out! at 2:26 PM on July 17, 2020 [1 favorite]


I think the best you are going to do is absence of evidence.

To date, there are nearly 14 million confirmed cases of COVID-19. I am not aware of any reports of anyone ever getting COVID-19 from food packaging, from food itself, or from take-out food. I have only heard one case of infection via fomites (virus on the surface of objects, in this case an elevator).

It appears that such infections are vanishingly rare, if they happen at all.
posted by Winnie the Proust at 2:39 PM on July 17, 2020 [3 favorites]


Best answer: A lot of the "don't touch your face / mouth / nose" is standard advice that is given for *all* diseases. This is obviously much easier messaging than "try to avoid cholera by not getting the bacteria in your digestive track, avoid flu by not getting it in your respiratory track, etc." So no one is ever going to withdraw this advice. But, as noted in Lexica's link above for SARS-CoV-2 this was emphasized more earlier, when generic advice like that (and unfortunately "masks aren't that helpful") was all we really had.

In general it seems the importance of surface transmission from an object is quite low. When I hunted around a few weeks ago it seemed there wasn't a single clear cut case (for example I pasted a link below from late May). Again, this is not the same as zero risk, but I'd say it's definitely not the surface transmission possibility that makes it scarily infectious.

There is also currently no reliable evidence of transmission of the virus via contact with contaminated objects or contaminated surfaces, which would have led to subsequent human infections. However, transmission through smear infections via surfaces that shortly before have been contaminated with viruses cannot be ruled out.
posted by mark k at 2:44 PM on July 17, 2020 [3 favorites]


Best answer: So as we all know absence of evidence is not evidence of absence.

That's a phrase that's too catchy, and of course even as originally applied (to WMD's in Iraq) led to the wrong conclusion. Absence of evidence isn't dispositive, but if you look for evidence where it should be and don't find it that means something.

Have people been looking? There've been a lot of case studies trying to nail down sources and they come down to airborne / droplet transmission. When I did my search for details on this there was one case of *maybe* surface transmission from factory equipment, but direct transmission could not be ruled out.

The obvious question if could we detect food transmission, given how easy airborne transmission is?

I actually think the answer is yes. Imagine a situation where an asymptomatic kitchen staff member was shouting, exhaling, etc. around food, maybe not washing their hands as much as they should. This obviously happens and *must* have happened statistically speaking many times in the millions and millions of known cases. Then you'd expect to see cases of clusters of diners getting sick with no direct contact. You can imagine more scenarios that could have been detected and haven't been yet.

So can it be ruled out? No. But would we know if it was happening frequently? Yes.
posted by mark k at 2:54 PM on July 17, 2020 [3 favorites]




Best answer: With viruses or any type of infectious disease, it is not just a matter of "I contacted one infectious particle, now I'm dead!" but much more a matter of the exact degree of exposure over time to exactly what receptive part of the body.

Just for example, you could probably soak your toe in a full solution of coronavirus all day long and yet never contract the disease--assuming you were somehow able to do this in a way that didn't also involve aerosolizing the virus and breathing it in. High exposure, long time period, extremely non-susceptible part of your body = no infection.

Even if you breathe in the virus, let's say you only breathe in a dozen or two live virii that happen to land in a susceptible place. In that case, your immune system will almost certainly kill those babies off and result: no infection.

But next time you breathe in say 10,000 virii at once, and ballgame over. It's too many for your immune system to deal with.

And by contrast, let's say you keep breathing in a dozen or two every hour for days and days on end. This is probably going to end up in active infection after a while, too.

Exposure rate over time => infection rate.

The reason for this is because your body has a wide variety of mechanisms for defending itself against such things as a virus. These range from barriers like your skin to the acidic conditions of your stomach. And especially, your immune system.

And the virus has particular conditions it needs to replicate and invade your body. Not every situation meets those conditions.

And then, even when a certain situation DOES meet those conditions, then it boils down to a real quick bout of warfare between your immune system and the invader.

One or two or a couple dozen or maybe even a few hundred or a few thousands of the virii, and your immune system can shut them down.

But there is some threshold above which your immune system is overwhelmed and can't deal with the invader, the invader gets the upper hand and is able to replicate at a faster rate than the immune system can kill it off, and there you go with infection.

So one reason it is complicated and not just a matter of "I breathed in 1 virus and then I died!!!1!!!" is that the whole thing is a giant war and a kind of an arms race between the virus and your immune system, with the surrounding environment as a sort of third-party player or spoiler.

Only when the virus travels successfully across space to reach your vulnerable systems, and then also gets the upper hand over your immune system to certain degree does it become and active infection that you notice or that is detectable.

And, again, this comes down to amount of exposure, duration of exposure over time, and whether the exposure is hitting a system of your body that is susceptible.

Finally: Each one of those variables I just outlined is highly, highly variable depending on exact biological properties of the virus, your immune system, the environment, and your body's other defenses. That is why it is not easy at all to predict ahead of time the exact behavior and infective routes or strength of a particular virus or other infective agent.

Just for example, this particular coronavirus doesn't seem to survive a trip down through the digestive system in such a way that it is (very?) infectious along the way. By contrast, for something like the norovirus, taking a ride through your digestive system is its very, very favorite way to propogate. Whereas if you breathed norovirus into your lungs, maybe nothing at all would happen.

It's all very, very specific to the biology of the situation.

I'm no expert on that but that is what I learned listening to the This Week In Virology podcast, which I highly, highly recommend.
posted by flug at 7:37 PM on July 17, 2020 [10 favorites]


> if we're not supposed to touch our mouths, why is it okay to put hypothetical virus-covered food in our mouths

#1. if you are touching your mouth with your virus-covered fingers you are almost certainly going to be touching your nose & eyes with them as well.


Whereas your pizza or salad, maybe not so much.

Most of us to try avoid rubbing pizza and salad all over the mucous membranes of our nose and eyes, for example. This is a pretty easy thing to do and if you fail to do it you will notice rather immediately due to excruciating pain and irritation.

Let's say the nasal mucous membrane is a potential avenue of infection (not sure if this is true of coronavirus or not, but let's say we're concerned about nasimucovirus and that is its main vector of infection). Even though rubbing your pizza on this membrane is a theoretical vector of infection, in real life you could probably eat infected meals 3X daily for 42 years without ever actually transmitting via that vector even once.

So theoretical yes, practical no. In the case of COVID-19, we now know empirically that transmission via food prepared by an infected person is a rare or almost nonexistent mode of transmission, for whatever variety of reasons.

#2. Your nose, eyes & mouth are in generally the easiest/most common transmission route for a wide variety of different infectious agents. So the only sensible generalized health-related instruction is to just minimize touching all of them as they are, in general, receptive surfaces and openings in your body.

This is basic no-brainer health messaging that is always true in general and is always going to help, sort of like do some daily exercise and eat some veggies every day.

It's a sensible general bit of advice and likely helpful to some degree in this particular situation and if we found out three years later due to exhaustive experimental evidence that "Well actually you can touch your tongue and throat with coronavirus all day long with no ill effects, and your eyes, too, but not your nasal opening" then there is really nothing lost in the meanwhile by being a bit more comprehensive.

#3. Certainly different types of virus, for example, are going to be more susceptible to mouth transmission, others more so to nose, others more so to eyes, or whatever (I can think of examples of all of the above and I don't even know much about medical things. However I guess I have contracted a bunch of different diseases over the years).

But it would be really kind of dumb medical advice to give people, something like, "OK, everybody, it is blorgavirus season and it transmits through your mouth and nose but not your eyes at all. So keep those fingers off your mouth & nose but go ahead and put them on your eyeballs to your heart's content!

"And now it's snorglavirus season, and that transmits to your lips and eyes but your nose is immune. So go ahead and bury your fingers up to the third joint up any nostril you choose, dig away to your heart's content! But, be carefully not to touch your nearby mouth & nose while you're at it--super dangerous!"

None of those make any sense as health messages. Just minimize touching altogether, and wash hands before times when you need to do so, for whatever reason.

#4. Let's look at risk analysis.
If you stop touching your eyes, mouth, and nose then you continue living happily, probably a little more healthy than before.

Risk of applying this health intervention: No downside, only potential upside.

Now: All food might be contaminated with the virus, so just stop putting anything at all in your mouth, to be safe! No eating, no drinking, etc.

Risk of applying this health intervention: Downside: You will die of starvation. Upside: Maybe you won't catch coronavirus if eating things is an infection vector."

If we did discover that food prepared by others was an important vector, then we'd find some way to deal with that fact and work around it.

But on balance, touching your various bodily orifices, the risk analysis says: don't; not worth the risk.

Eating food, the risk analysis say: do; it's well worth the risk.
posted by flug at 8:03 PM on July 17, 2020 [2 favorites]


Best answer: "Can the virus live on the surface of food?" is "Coronaviruses cannot multiply in food." You may notice that is not an answer to that question. Or maybe it is, and I don't see it because I don't understand viruses.

It kind of is. Viruses don't meet a lot of the definitions of "living": they don't breathe or eat or otherwise metabolize any incoming substance to produce energy, they don't move under their own power, they don't grow, they don't adapt or respond to stimuli. About the only thing they do that's adjacent to normal definitions of living is that they do reproduce - but even there, they need to be in contact with an actually living organism to accomplish that. So the answer is addressing the one aspect of the question that it can; the problem is really that the question is built on a mistaken assumption. Which was probably intentional, that probably is how a lot of people ask the question they think means the same as "Can the virus remain on the surface of food intact and in sufficient numbers to pose a risk to me?"
posted by solotoro at 6:45 AM on July 18, 2020 [1 favorite]


The reason why virologists think "the virus cannot multiply on food" is a key part of the answer, is because if it can't multiply all it can do is degrade. Acid, heat, various chemical reactions, UV light, all sorts of dangers exist in the world for a virus outside of a cell. It doesn't just sit dormant for all of time waiting for a victim to walk past.

The other observation that's been made above that I want to echo is about outbreak patterns. If this virus were food transmissible, then in the countries that are doing contact tracing they would have seen outbreaks associated with food sources. A cluster who got carry out from this particular place on a particular evening, or people eating at a restaurant being sickened by a food service worker in the back of the house.

How many restaurants are there operating in the COVID hot spots of the world, and how many of those back of house workers can afford to take off a day just because they're starting to get the sniffles? There have been a lot of opportunities for food transmitted outbreaks, if this virus were contagious that way. Instead we see a bunch of cases of diners being sickened by diners at other tables, and transmission from diners to staff, or between staff to each other.
posted by Lady Li at 8:04 AM on July 19, 2020 [2 favorites]


So, absence of evidence is not evidence of absence but there's lots of evidence that you can get other potentially serious diseases from food - stuff like norovirus, salmonella, and even Hep A. To use Hep A as an example, in the US it's mostly transmitted person-to-person, but occasionally outbreaks are traced to contaminated food and water - there are, on average, 6 foodborne outbreaks of Hep A in the US each year, and many more worldwide. There was a suspicious cluster of cases linked to a restaurant in Seattle earlier this year. In contrast, so far there have been no documented foodborne outbreaks of COVID-19. Of course we have a lot less data on COVID-19 in general, since it's only been around for six months. But still, the evidence suggests that contaminated food is very low-risk.

Basically, you're probably at higher risk of getting some *other* serious foodborne illness than of getting COVID-19 from food.
posted by mskyle at 8:47 AM on July 19, 2020


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