Don Schaffner is a professor of food microbiology at Rutgers School of Environmental and Biological Sciences.  He hosts two podcasts called Food Safety Talk and Risky or Not?  Here he refutes a widely seen video which urges everyone to go to great lengths to wash their groceries.

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.

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.

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.

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.

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.

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?

This also has very important food safety implications. This sounds like a recipe for disaster, or at the very least spoiled food.

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.

But this advice presumes that all groceries are contaminated, and the simply touching the groceries will make you sick, neither of which are true.

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.

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.

And guess what, washing your hands before you eat is a best practice even when we’re not in a pandemic!

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://twitter.com/bugcounter/status/1242956925525995521…

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.

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”.

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.

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.

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.

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.

If your hands are getting dry from too much handwashing, be sure to use some moisturizer.

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.

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.

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.

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.

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.

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.

You should also wash your hands after you have finished putting all your groceries away. This was also a good advice even before pandemic.

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.

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.

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.

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.

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.

PS, thank to everyone for the Twitter/Facebook 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.

Keep an eye out for the kids!