Many areas in the country are seeing fewer COVID-19 cases. Yet front line food workers from the fields to the factories have been hit hard by COVID-19 infections. This has raised concerns about food safety, particularly in fresh produce.
To date there has been no confirmed transmission of COVID-19 from food of any kind, but people at high risk for COVID-19 infection and complications may still not feel at ease about eating fresh produce. Antioxidants found in fresh produce are critical to optimize our immune systems. Cooking to temperatures above 170F will kill the virus, and other safe food prep practices can further minimize the risk of all pathogens. But it seems that plants themselves may have a role in controlling the amount of viable viral particles on their surfaces.
In this study, researchers tested a variety of produce for the ability to harbor and spread viral particles. Berries and lettuce samples were inoculated separately with coronavirus, adenovirus, and poliovirus. The produce was then incubated in a refrigerator to simulate home storage and were processed at various time intervals (1, 2, 4, 8, or 10 days). After storage, coronavirus was undetectable on strawberries and 19% recoverable on lettuce. In contrast, poliovirus was 76% recoverable from lettuce, while adenovirus persisted and was 56% recoverable from lettuce and 31% recoverable from strawberries. While viruses were not completely curtailed, populations were significantly reduced over 2-4 days in storage, especially for the more easily disrupted envelope viruses like coronavirus. Researchers believe it may be the antioxidants on which our immune systems rely that are partly responsible for curtailing COVID-19 in food.
Antioxidants have long been studied for their antimicrobial and immune boosting effects. The presence of quercitin and other antioxidants found on the surface of produce may also play a role. Plant compounds including saponins (in legumes, quinoa), thiosulfinates (onion and garlic), glucosinates (broccoli family), terpenoids (citrus and cinnamon), and polyphenols (berries, apples) have been shown to have antimicrobial properties against other envelope type viruses. These antioxidants might not only reduce viral particles on the surface of produce, but also protect us after we eat them.
Simple household food chemistry may also be effective in reducing viral volume. White wine vinegar which is 6% acetic acid, was found to reduce SARS-CoV by a factor of 3 log in 60 seconds. 70% propanol used in hand sanitizer performed similarly at 30 seconds. While you don’t want to soak produce in hand sanitizer, you can use good old acetic acid, or vinegar to help lower potential viral loads on your produce. You can also peel produce and discard outer layers of lettuce and cabbage before washing, or simply cook all of your fresh produce until you feel it’s safe enough to eat it fresh. We don’t currently know what amount of virus is necessary to cause infection, but any reduction in potential exposure is a step in the right direction.
There will always be some risk associated with eating fresh produce. But consumers have tools to help mitigate those risks. Use care when unpacking all types of groceries, wash produce with water or produce wash, and consider a short soak or rinse in vinegar. Always cook foods to proper temperatures to ensure safety from all types of food borne pathogens. The focus may be on COVID-19, but our risk of food borne illness from all pathogens remains. Don’t lose sight of your nutrition. Now more than ever It’s important to get the nutrients you need. Your health depends on it.