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Food & Drink Features

What science says—and doesn’t say—about how to clean fresh fruits and vegetables

While there are a lot of homegrown methods of washing fresh fruits and raw vegetables, based on existing research, the best way to clean them is still with plain water. By ROMMEL SIM GERODIAS
| Apr 13 2020

People are understandably apprehensive, now even more than before, about consuming food that is safe and free of contamination, moreso for fresh fruits and vegetables that we eat without cooking. As of today, the US Centers for Disease Control and Prevention states, “Coronaviruses are generally thought to be spread from person-to-person through respiratory droplets. Currently there is no evidence to support transmission of COVID-19 associated with food.”

While the coronavirus is foremost on our minds, take note that contaminated produce can involve more than just viruses. In the United States, federal health officials estimate that nearly 48 million people are sickened by food contaminated with harmful microorganisms each year. In recent years, the United States has had several large outbreaks of illness caused by contaminated fruits and vegetables—including spinach, cantaloupe, tomatoes, and lettuce.

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Fresh fruits and veggies travel through many places before they reach our tables, exposing them to many elements. Photo by Anne Preble for Unsplash

Fresh fruits and vegetables make up part of a healthy diet, and are available in supermarkets and public markets. However, we know that these fruits and vegetables travel through many places before they reach your lunch box or dining tables. As they are harvested, some of the produce may have had contact with contaminated soil or water along the way, making them carriers of pathogens that may cause foodborne illnesses. From harvest to processing to packaging and even at point of sale, they continue to get contaminated.

Especially for produce that is ready to eat—fruits like apples, grapes, strawberries that don’t have to be peeled, or raw herbs and vegetables used in salads and as garnishes—we must be very careful and take necessary steps to ensure that they are safe for eating.

Store perishable fresh fruits like strawberries in a clean refrigerator at a temperature of 5°C or below. Photo by Charles Deluvio for Unsplash

Buy right. Store right.

You can help keep your produce safe by making wise buying decisions and keeping them safe throughout the flow of food.

  • Choose produce that is not bruised or damaged.

  • When buying pre-cut, bagged, or packaged produce—such as half of a watermelon or bagged salad greens—choose only those items that are refrigerated or surrounded by ice. Refrigerate right away when you get home.

  • Bag fresh fruits and vegetables separately from raw meat, poultry, and seafood when packing them to take home from the market.

  • Store perishable fresh fruits and vegetables (like strawberries, lettuce, herbs, and mushrooms) in a clean refrigerator at a temperature of 5°C or below.

Photo by Louis Hansel for Unsplash

Prepare safely.

Supermarkets and public markets, generally, don’t wash fresh fruits and vegetables before putting them out. So it is best to wash fresh produce properly before prepping, cutting, or eating.

  • Wash your hands for at least 20 seconds with soap and warm water before and after preparation.

  • Cut away any damaged or bruised areas on fresh fruits and vegetables before preparing and/or eating.

  • Throw away any produce that looks rotten.

 

Wash properly.

In one of its bulletins, the University of Maine Department of Food Science and Human Nutrition, and Cooperative Extension gives the following tips:

  • Use clean potable cold water to wash items.

  • Produce with a lot of nooks and crannies like cauliflower, broccoli, or lettuce should be soaked for 1 to 2 minutes in cold clean water. Repeat as many times until no soil is falling off the water.

  • Some produce such as raspberries should not be soaked in water. Put fragile produce in a colander and spray with distilled water.

  • Eating on the run? Fill a spray bottle with distilled water and use it to wash apples and other fruits.

  • Wash greens by separating leaves and soaking them in a bowl of cool water for a few minutes. Drain leafy greens with a clean strainer or colander, then dry with a clean disposable towel or salad spinner. Salad spinners should be thoroughly washed, rinsed, and sanitized before and after every use.

Photo by Louis Hansel for Unsplash

What about pre-washed produce?

According to the US FDA, many pre-cut, bagged, or packaged produce items are pre-washed and ready to eat. If so, it will be stated on the packaging, and you can use the produce without further washing. If you choose to wash produce marked as “pre-washed” or “ready-to-eat,” be sure that it does not come in contact with unclean surfaces or utensils. This will help to avoid cross contamination.

 

Can detergent or soap be used to wash produce?

You shouldn’t use soap or any detergent in washing your fruits and vegetables. Detergent residues and other chemicals which may not be safe for consumption can be absorbed by the produce skins and peelings.

 

What about vegetable wash products?

In a home setting, if you choose to use a commercial vegetable wash, follow the manufacturer’s instructions. The product will clean the produce, but no research to date has indicated that it does any better job than just plain water.

Photo by Manki Kim for Unsplash

Can fresh produce be cleaned using vinegar?

While there are many articles online that suggest doing this, it may turn out that cleaning fruits and veggies with vinegar is a myth. I couldn’t find any scientific study or government standards to back this up. In truth, most studies made by universities and scientific research tells us to wash fresh produce with potable water only, as pesticides and other possible contaminants are usually soluble in water. They will come off easily with a plain water rinse, as a study from the University of Minnesota Extension notes. However, another study in the Journal of Agriculture and Food Chemistry finds that using baking soda diluted in water is effective to remove pesticide residue, but only from the skin of the produce.

 

Does clean water eliminate viruses and bacteria from fresh produce?

At home, simply washing the vegetables with water will do the job of removing bacteria, virus, and parasites if done properly as described above. While commercial restaurant operations do use food grade chlorine bleach solutions to sanitize raw fruits and vegetables, these are done under specific guidelines and not available for home use. That’s why I cannot recommend chemicals for home use as available household bleach products like Zonrox are not guaranteed to be food grade.

The US FDA advises that we all adopt these everyday safe food handling and hygiene practices to avoid foodborne illness. And it is worth reiterating that, according to the US FDA, there is currently no evidence of food or food packaging being associated with the transmission of COVID-19. 

 

Sources:

https://www.restaurant.org/COVID19#spread

https://extension.umaine.edu/publications/4336e/

https://extension.wsu.edu/foodsafety/content/washing-fresh-produce/

https://www.fda.gov/consumers/consumer-updates/7-tips-cleaning-fruits-vegetables

https://inspection.gc.ca/preventive-controls/fresh-fruits-or-vegetables/chlorinated-wash-water/eng/1524255855330/1524255855736

https://www.livestrong.com/article/255880-how-to-clean-fruits-vegetables-with-vinegar/

https://www.ncbi.nlm.nih.gov/pubmed/29067814

https://www.fda.gov/food/buy-store-serve-safe-food/selecting-and-serving-produce-safely
https://ucfoodsafety.ucdavis.edu/sites/g/files/dgvnsk7366/files/inline-files/26437.pdf

https://www.fda.gov/food/food-safety-during-emergencies/food-safety-and-coronavirus-disease-2019-covid-19

 

The author is a food safety consultant and auditor, a ServSafe Certified Trainer and Proctor, president of A101 Innovations, Inc., and consultant for Hauptmann Consulting and Business Solutions.