On Sunday, I posted an article about sanitizing your food after you return from grocery shopping. The thing is, the medical professional who posted the original clip went a bit overboard in terms of how sanitary he felt he needed to keep his food once retrieved from the grocery store. The truth is, not everything the doctor says in his video is strictly correct and he is no food safety expert, as has been pointed out to me. However, for the most part my textual commentary doesn’t contradict what I’m about to share and I am happy to give Dr. Don Schaffner his due:
Unless you are living under a rock or have already perished from COVID-19, you’ve likely seen a YouTube video making the rounds where a medical doctor (wearing scrubs!) purports to give COVID-19 advice. (1/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Buckle up, readers, as it’s about to get serious! Thirty-two more tweets, seriously!
I’m not going link to the video, because if you haven’t seen it, consider yourself lucky. First of all, scrubs? Aren’t those meant for being around sick people? Why would you wear something like that in your house. It seems very irresponsible. (2/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Unfortunately, the link above to my original article with take you to that video but if you haven’t hit play on the video, and just read my commentary, you should be fine. Please, trust Dr. Don!
I’m a food microbiologist. Would you like me to give you advice on how to care for your sick kids? I don’t think so. Don’t take food safety or microbiology advice from MDs that don’t understand food, science or very much about microbiology. (3/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Sometimes I roll my eyes at my fellow writers when they they try to come up with Science Fiction ideas, since I did study undergrad Physics and read a lot of science books. I feel you Dr. Don!
There are a few things that he gets right, but I’m not going to focus on those. I’m going to spend my time here focusing on the things that he gets partly or completely wrong. (4/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Here here! I already outlined most of what was right in the video in my original post. I think I may have misspoken on how to wash produce but I’ll save that commentary for later.
He completely misrepresented the 17 days figure from CDC. This was based on finding viral RNA, not infectious viral particles. The CDC report also does not give the methods used but cites personal communication… impossible to peer review. (5/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
There’s a bit of nuance to this, but what the good Dr. Don is saying is there is a difference between a random but not yet denatured strand of viral RNA, which in itself isn’t particularly harmful—at least, not infectious—where as a live virus was not observed. As in, the crown-like outer shell of SARS-CoV-2, a.k.a. the Coronavirus, the “Crown Virus”. Without the outer shell and crown-like protrusions, the virus has no way of penetrating cells, be they eukarya, bacteria, or archaea. Note, this pathogen only infects eukaryotes, though most viruses are harmless, only infecting bacteria.
More fundamentally, though, Dr. Dan points out that the CDC Study that came up with the 17-day number for RNA was never published in a peer-review paper where the methodology and techniques used could be scrutinized and dissected. Without the process of peer review, the observation is as good as anecdotal.
Should I keep my groceries in the garage or on the porch for 3 days? This is patently ridiculous. Are you really going to keep your milk, your ice cream, your deli meats outside for three days? (6/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
This was one of my biggest beefs with the video too. I mean, it’s one thing in the winter in Lansing, MI, where the outside might already be the temperature of your freezer. But that won’t work in Florida, not by a long shot. So unless you’re gonna be like Thomas Jefferson and truck in ice from Canada to keep your food from spoiling, don’t leave your perishable food in the garage!
This also has very important food safety implications. This sounds like a recipe for disaster, or at the very least spoiled food. (7/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
There is a tiny nugget of truth in this advice, because we know that the virus is slowly inactivated at room temperature, with a half-life of about eight hours. (8/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
This is a very good point. One of the ways the SARS-CoV-2 deactivates is through desiccation. If the virus is in a medium that allows it to dry out, it will no longer be effective. This is why spittle from sneezing is the most dangerous.
But this advice presumes that all groceries are contaminated, and the simply touching the groceries will make you sick, neither of which are true. (9/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
The virus is highly communicable, to be sure, but its transmission with respect to someone with the virus touching an item on the shelf, putting it back, and then having you grab it is exceedingly unlikely. And by the time you get to it, it’s quite likely SARS-CoV-2 has already dried out and perished.
Do I really need to disinfect all of the individual boxes & baggies everything came in? I also think that this is also advice that does not make scientific sense. (10/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
I have to agree, as different packaging materials will allow the virus to remain active long than others, and again, as state above, it’s unlikely by the time you pluck the item from the shelf that it would still have any active virus on it even if it had once.
If you are concerned about the outside of food packages being contaminated, I suggest that you wash your hands and or sanitize your hands before you sit down to eat any food that you might’ve taken out of those containers. (11/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Washing your hands before eating should be second nature anyway. As Dr, Don says, you can remove the item from the packaging, put it on a clean plate, and then wash your hands before eating and any contamination on the packaging will have been removed from the equation.
And guess what, washing your hands before you eat is a best practice even when we’re not in a pandemic! (12/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Do I really need to scrub all your fruits and veggies with soap before eating? This is the worst advice being given by this irresponsible MD. Soap should *absolutely* not be used to wash food. See my earlier comments: https://t.co/EM2oylio0e (13/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
There are good reasons not to use soap to wash your produce and I will admit I got that wrong before. Soap dissolves cell membranes and while most produce is covered by dead epithelial cells—like those on the outer layers of your skin—and thus won’t likely cause cellular damage to your food, but if you slice the food it could spoil its flavor and if you fail to wash it all off and it gets in the nooks and crannies of your consumables, Dr. Don is right, you’re itching for a tummy ache. The oily residue soap normally removes isn’t a big issue on produce and thus a simple water bath should be sufficient for cleaning your produce.
Soap is not designed for food. As mentioned in the linked thread, soap can cause nausea, vomiting and diarrhea if ingested. Current recommendations by scientific experts including the FDA, say to wash fresh fruits and vegetables in cold water. (14/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
He also seems to have a belief that I find surprisingly common (including among food safety professionals). That is the belief that I referred to as “handwashing is magic”. (15/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Even the prescient Dr. Ignaz Semmelweis knew that hand washing wasn’t a panascia. It reduces the change of killing a mother giving birth, but even if done right, it isn’t perfect. Soap and water are great for removing both hydrophobic and hydrophilic substances from your person, but not every pathogen is removed by such reactions. SARS-CoV-2 is damaged because of its hydrophobic coating, but the same isn’t true for all toxic substances.
Hand washing is not magic, nor does it “sterilize” your hands as claimed in the video. The only way to sterilize your hands would be to plunge them into boiling water, which I don’t recommend for obvious reasons. (16/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Indeed, human skin has many friendly microbes that help keep the skin clean and fresh. You wouldn’t want to boil those off anyway, even if you could. Love your friendly microbes. Just use soap and water to kill SARS-CoV-2. That M*th*r F*ck*r must die!
We’ve done research on handwashing in my lab. You can count on a hand wash (depending upon your technique), to likely give you somewhere between a 90 a 99% reduction in transient microorganisms on your hands. (17/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
This is another good point. Not all handwashes are equal. I try to do a rather complex technique when washing my hands which I may document another day, but the long and short of it is, just rubbing your hands together isn’t enough, and even my technique isn’t one hundred percent effective.
A microbiologist would call this a 1-2 logarithm reduction. Let’s contrast that with the sterilization process used for canned foods. That would give you a 99.9999999999 percent reduction. In case you’re counting, there’s 12 nines in that number. (18/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Great point! Early food preservation in wine bottles with their tartaric acid may have worked for Napoleon’s army, but when we started using steel and aluminium cans, or even glass, we had to be very very sure everything was sterile. Watch any number of episodes from Comment C’est Fait (How It’s Made chez É-U.) to see how this is done.
Is washing your hands good? Of course it is. Is it going to sterilize your hands? Absolutely not. But it is a good risk reduction technique. As is the use of hand sanitizer. So do both of those things. (19/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Remember the words of François-Marie Arouet, a.k.a. Voltaire, “Le mieux est l’ennemi du bien.” (Perfection is the enemy of good.)
If your hands are getting dry from too much handwashing, be sure to use some moisturizer. (20/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
This is one point I did make in my original article. Glad to see my point is backed up by Dr. Don.
Also re: washing produce, people may wonder about “veggie wash” products. Many of these have not been evaluated for their effect on bacteria and none have been evaluated for their affect on SARS-CoV-2, the causative agent for COVID-19. (21/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
This one is simply a caveat emptor. Don’t assume a product can kill viruses. Indeed, there are many ways product makers can use language that makes it seem like it’s effective against pathogens, but unless there is peer reviewed literature to back it up, sorry, it’s not magic. It won’t protect you against SARS-CoV-2 any better than simply washing your hands.
Many of veggie washes are likely no more effective than water. On the other hand, if it makes you feel better, and you don’t mind throwing money to the veggie wash company, I say go for it. (22/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
There is something to be said for the security blanket of feeling better. But, yes, they won’t help and are no better than a simple cold-water bath.
Some people are also asking about vinegar for washing fresh produce. Again the research says it’s not much better than plain water. Save the vinegar for oil and vinegar dressing on your salad. (23/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Or for treating the fabric of your home made N95 mask.
Are reusable bags risky? Many people use reusable bags as a responsible choice. We do this in my family as well. It’s a best practice (even before the times of pandemic) to wash your reusable bags on a regular basis. (24/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
I like using reusable bags and agree washing them like any fabric is a wise idea. If you must use disposable bags, please use ones that are recyclable or compostable.
While it is theoretically possible that a reusable bag may pick up germs, including coronavirus while in the grocery store, the biggest threat that anyone faces is someone else in the store who has COVID-19. (25/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
In other words, keep your bags close but be more mindful of social distancing and that the bagger uses proper sanitary techniques. But again, the likelihood that someone with the virus has used that same checkout stand recent-enough for the virus to still be active is very likely, and most grocery stores, like Wegman’s will do their best to sanitize the checkout counter between each customer during Covidapolis.
I would suggest that you keep your grocery bags in the car, so you have them handy the next time you go shopping. If you’re concerned that your bags might have coronavirus on them you can wash them. (26/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Keeping them in your car is a good idea. I always keep my MOM’s Organic Market bag in my car so it’s ready whenever I go there.
You should also wash your hands after you have finished putting all your groceries away. This was also a good advice even before pandemic. (27/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Wash your hands!
But Dr. Don, what I can do to reduce risk when grocery shopping? Many grocery stores are offering hand sanitizers at the entrance, and are offering to sanitize grocery carts. Both great ideas, and customers should take advantage if available. (28/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
I have indeed noticed Wegman’s doing just that. They are, IMHO, doing a great job!
My other advice is to make a list, and know what you want, and move quickly and efficiently through the store picking out the items on your list. Practice appropriate social distancing, trying your best to keep 6 feet away from other shoppers. (29/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Know what you want, like Low Acid Orange Juice, and head straight over. Keep those two meter buffers to keep safe!
If there is hand sanitizer available, I also use it when I’m exiting the store, and then I’ll use it again at home once I finished putting all my groceries away and returning my reusable shopping bags to the car. (30/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
If you can get hand sanitizer, then it’s great when there isn’t soap and water available. But when you have soap and water, always prefer that.
I’m going to ask you to share this tweet thread. As the video MD said it’s not about popularity. In my case it’s about combating harmful misinformation that overestimates risk, or recommends risky practices to mitigate an already very small risk. (31/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Done in the most complete way possible Dr. Don!
This has been Dr. Don… now signing off. Remember as always, stay home if you can, wash your hands and use hand sanitizer, and take care of those who need it most.￼￼ (32/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Shelter in place, y’all, and use Zoom to see a friendly face!
PS, thank to everyone for the Twitter love. I’ll do my best to answer questions you have, but right now my days are filled with talking with reporters, and trying to achieve a one log reduction on the concentration of email messages in my inbox. (33/33)— Don Schaffner 🦠 (@bugcounter) March 26, 2020
Much obliged Dr. Don! Happy to help promote good science, sound food handling, and how to weave a great yarn, and sew a great mask!
Bon appetit, mes amis!
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