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The risk is small, but here’s why you should still wash your produce.

Hugh Garvey  – April 8, 2020 | Updated April 12, 2020

In the era of of corona the ritual pleasures of spring can be tinged with dread. Mask-wearing, begloved home cooks warily eye the produce section like it’s a cornucopia of viral vectors. Could those baby asparagus be harboring your demise? For those fortunates whose local nurseries have been deemed essential services, even a contactless pickup can lead one to question a tomato plant’s potential role in the pandemic. To get some clarity we spoke with Charles Gerba, an award-winning environmental virologist at the University of Arizona who has been studying how viruses are transmitted through food, water, and air for the past 40 years.

During the original SARS coronavirus pandemic in 2003, Gerba flew to Southeast Asia to assess the potential foodborne pathways for the World Health Organization. In 2013 he co-authored a study that examined the survival time of coronavirus on the surface of fresh produce. Gerba and his fellow researchers placed coronavirus on lettuce, strawberries, and raspberries and stored them in conditions that mimicked the temperature and humidity of a household refrigerator. The study determined that coronavirus could live from 2 to 4 days on lettuce and raspberries. That sounds scary. But is it? We got on the phone with Gerba to find out. 

The World Health Organization and the FDA have both said there’s no evidence that a person has been infected with coronavirus through food.

Just because there’s no evidence doesn’t mean it’s not possible, but it would take a study of a million people to find out. Like they say, until you look you don’t know. During the original SARS pandemic I went to southeast Asia to explore whether foods could be a possible transmitter specifically because there was no data.

In your 2013 study, you found the virus could survive for several days on certain produce, but is that something we should be concerned about? The study also showed that the amount of virus that could be detected diminished quickly over time.

There’s a small risk there but I don’t think it’s a major issue. Theoretically you could eat the contaminated vegetables and possibly inhale some of the virus, but the risks of that happening are very low. The coronavirus is very fragile. If there was virus on the surface of the produce, you’d have to touch it, and the amount you picked up would have to be enough to get you sick, and you’d have to get that into your nasal passages. There is evidence that it can survive in your gut. But the risks are very low. That said, I definitely started washing all my vegetables after that study.

Does the surface of produce and vegetables affect the survival time of the virus?

Yes. The virus likes smooth surfaces. But just because it’s on something you still have to be able to get it off. If you touch stainless steel covered with virus your fingers will pick up 70 percent of the virus. If you touch paper, you’ll only pick up one percent.  We couldn’t even retrieve the virus from the strawberry because the surface was so rough. On the lettuce and raspberries it survived for around two days. If you ask me my opinion, you should always wash your vegetables.

Most people wash their vegetables before eating anyway, so they’re already engaging in best practices.

Yes. You have to remember with produce there’s a lot of handling. It’s handled when it’s harvested, packed, and then placed on the shelves. Even if the handlers are wearing gloves they can still sneeze or blow their nose on it. Coronavirus is very fragile so rinsing with water mixed with a little soap should be enough. But there are other potential pathogens like e coli 0157. To get rid of that you should wash it with a water and bleach solutions. You can look up the recommendations for exactly how much. Frankly I’m more worried about Hepatitis A in raspberries. While the risks are low, I still wouldn’t let anybody make me a salad with coronavirus.

What about plants we bring into our homes? If I bought a rubber plant from a nursery that someone with coronavirus had sneezed on would I be able to pick up the virus with my hands, rub my eyes or nose, and infect myself?

That’s a possible transmission path but I’m not much into fondling plants. I might not smell the flowers though.

Right, it’s a respiratory virus. Where would you put yourself on the spectrum of caution?

I’m on the overly cautious end of it. I look at the mortality for my age group and believe me I’m going to be overly cautious. 

If we practice social distancing, wash our hands, and wash our produce, is there anything else we should be doing to stay safe? 

Watch out for those shopping carts.

Why?

The reason grocery stores started handing out all those wipes is because studies have shown that upwards of 80 percent of grocery store carts can have diarrhea causing pathogens on them. 

That’s disgusting. 

You also have to be careful with your reusable shopping bags. We conducted a study and the majority of bags we tested had e coli. Some of them had more e coli on them than previously worn underwear. So be sure to wash your reusable grocery bags or you might end up with salmonella salad you didn’t order. 

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