As uncertainty continues over the source of Germany’s E. coli outbreak, which as of Thursday had sickened 1,600 people and killed 18, one clear question emerges: If the food source turns out to be cucumbers, tomatoes or lettuce, so far the prime suspects, was it handled according to accepted food safety practices?


With that question, comes another: How should produce that will be eaten raw be handled and prepared to prevent food poisoning? That’s especially relevant this time of year, because  salads and raw fruit and vegetables are summertime favorites.

Fortunately, for the most part, if you’re a typical consumer, it’s fairly easy to make sure the raw produce you prepare is safe to eat. But there’s more to it than washing it properly. Following the Food and Drug Administration’s recommendations is an excellent route to keep yourself, your family, and friends safe from food poisoning.

These FDA recommendations apply to all produce — including organic produce or even produce from your own garden or orchard — not just what you buy in the grocery store.

Buying produce

It starts out in the grocery store or at the farmers market or farm stand. When considering which vegetables and fruits to choose, avoid any that are bruised or damaged, which would include even minor breaks in the surface. That’s because bacteria can hide in the damaged areas and from there spread rapidly through the rest of the vegetable or fruit.

In the case of fresh-cut produce — bagged lettuce greens or sections of watermelon or cantaloupe, for example — make sure they’re refrigerated or surrounded by ice.

To avoid cross-contamination, don’t put fresh produce in bags with meat, poultry or seafood products. For the same reason, make sure that the cashier doesn’t mix the two. You need to keep them separate.

Storing and preparing produce

Once home, put the raw produce in the refrigerator, checking to see that the temperature is 40 degrees F or lower. For the most part, that temperature range not only maintains quality but also helps prevent the spread of any pathogens that might be on the surface of the produce. (If you’re not sure about what temperature a specific kind of produce should be kept at, just ask the grocer or farmer.)

When you’re ready to prepare the produce, start off by washing your hands with warm water and soap for 20 seconds — before (and after) preparing and/or eating the produce.


Cut away any damaged or bruised areas. Then gently rub the produce while you hold it under running water. The FDA says there’s no need to use soap or a produce wash. If you plan to peel the produce, which is often the case with cucumbers, make sure you wash it before you peel it. And make sure the utensil you’re using is clean.

When washing firm produce, such as cucumbers or melons, use a clean vegetable brush to scrub while you hold the vegetables under running water.  Follow that up by drying the produce with a clean cloth or paper towel. This helps to further reduce bacteria that might be present on the surface.

To avoid cross-contamination, it’s also important to wash cutting boards, dishes, utensils and countertops with hot water and soap in between preparing meat, fish or poultry products and produce that isn’t going to be cooked. Periodically use kitchen sanitizers on cutting boards and counter tops. As for plastic or other non-porous cutting boards, just pop them into the dishwasher after using them.

Greg Komar, director of food safety for Growers Express, told Food Safety News that it’s also important to wash all the plates and bowls that you’ve used to store fresh produce after every use.

“Filth, flies, and insects can also be a vector of contamination, and so if there are old vegetable (or fruit) materials in a bowl or on a plate, they might attract these insects,” he said.

Going several steps further, a study done by Cook’s Illustrated, revealed that while a scrub brush and water will remove about 85 percent of bacteria, the cleaning method that worked the best was a dilute vinegar rinse or soak, which removed up to 98 percent of bacteria.

In the case of smooth-skinned produce, Cook’s recommends mixing one part white vinegar with three parts water. After shaking the solution well, spray the fruits and vegetables with enough of the solution to cover the entire surface. Follow this step by rubbing the produce gently with your clean hands to make sure the solution covers all of the surface. Let it remain on the produce for 2 or 3 minutes and then thoroughly rinse the fruit or vegetable under cold water, scrubbing firm produce with a brush and rubbing soft produce with your hands. Finish up by patting the produce with a clean towel.

Another tip, when applicable, is to slice the blossom and stem ends off fresh produce after washing it because bacteria and dirt are often trapped there.

Even though meat, poultry and seafood have been major players in food poisoning outbreaks caused by pathogens such as E. coli and Salmonella, raw spinach, peppers and other produce have also triggered outbreaks, some of them deadly.

“Raw is raw,” said Jim Cook, a food safety technologist with SGS a global testing, inspection, verification and certification company.  “All raw products, not just meat, fish, or poultry, can have pathogens. It’s just the nature of being raw.”

Cook said that SGS is currently “very busy” testing produce, especially cucumbers, in Europe.

Meanwhile, not all food safety experts believe that it’s solely up to the consumer to take steps against contamination that can cause food poisoning. Bucking what he says are industry-based “self-serving assurances” that consumers can prevent food poisoning by taking the proper steps when preparing produce, Roy Costa, a registered professional sanitarian, warns that if foodborne pathogens contaminate produce before the consumer buys it, there’s probably nothing the consumer can do to completely get rid of them.  

He rankles at the notion that puts the responsibility of making sure food is safe on the consumer.

“It’s the produce industry’s responsibility to make sure that produce isn’t contaminated during growing, packing and distribution,” he said.

Nevertheless, he agreed that choosing produce without blemishes such as breaks in the skin, bruises or decayed areas and then keeping it cool and washing it before preparing and serving it can help prevent food poisoning. But he also advises consumers to keep their ears open and their eyes peeled for news of recalls.

Can foodborne pathogens be inside produce?

A recent article in SpiegelOnline International pointed to research at the Department of Plant Pathology at the Scottish Crop Research Institute that discovered that E. coli pathogens on the surface of tomatoes and lettuce they studied migrated from the surface to lower layers of tissue to colonize the produce.

But Trevor Suslow, Extension research specialist at the University of California, Davis, who has statewide responsibilities in quality and safety of perishable horticultural commodities, said the jury
is still out on that one

“As far as I’m aware, none of these foodborne pathogens can penetrate the surface of produce on their own,” he told Food Safety News.

He said that it generally requires some sort of opening, such as a micro-wound on the surface, to open the pathway to the subsurface of the produce. But when that happens, even antibacterial solutions won’t be able to rid the produce of the pathogens.

Suslow will be working on a research project that seeks to expand current knowledge about the potential for cucurbits — a classification that includes cucumbers, squash, melons, pumpkins and gourds —  to internalize pathogens from their roots. But he suspects that internal contamination of cucurbits through that route is highly unlikely, because previous research on cantaloupe and watermelon showed that pathogens don’t appear to transfer from the roots into the fruit.

Growers Express’s Greg Komar would agree, saying that while he wouldn’t say that root uptake and internalization definitely doesn’t happen in produce such as cucumbers, he thinks “it is safe to assume” that it doesn’t.

He pointed out that cucumbers form after the flowers are pollinated, which means the bacteria would have to come up through the root, travel through the vein system of the plant, and get into the actual fruit.

“That represents a lot of travel so would seem unlikely,” he said in an email to Food Safety News.

David Gombas, top food safety official with United Fresh, pointed out that in the past 10 years, there has been only one food poisoning outbreak linked to cucumbers, and that link wasn’t confirmed.

The situation is similar on the other side of the Atlantic. Paul Hunger, a professor of Health Protection at Britain’s University of East Anglia, told a reporter that cucumbers are not normally implicated in food poisoning breaks because they’re so easy to clean and because bacteria are less likely to find a protected spot.

But in the case of cut salad greens, pathogens can be a problem on both sides of the Atlantic. That’s because when leaves are cut during harvest, nutrients begin to ooze from the cuts. That, in turn, attracts any pathogens that might be on the leaves or in the immediate area. When that happens, the pathogens cling tight and can’t be dislodged. But that only happens if there are pathogens present. If farmers and food handlers follow good agricultural and handling practices, there won’t be any foodborne pathogens on the leaves or in the immediate area.

Down on the farm

SGS’s Jim Cook said that from an industry perspective, food safety goes back to the field — that it’s important to have field conditions that don’t harbor foodborne pathogens such as E. coli and Salmonella. For that reason, the fields should be managed so they aren’t vulnerable to contamination by animals and birds.

Cook said another important food safety “must” on the farm is clean water. The water source for irrigation and cleaning the produce must be monitored and certified to be free of pathogens.

Once harvested, the produce must be stored under the right temperature, which is usually 40 degrees F. And that cold chain must be maintained all the way through, including during transportation.

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United Fresh’s David Gombas agrees.

“You want to make sure vehicles and containers are not the source of contamination,” he said.

Cook said that when buying directly from a farmer, you should ask if the farm is following good agricultural practices (GAPS) and federal food safety guidelines for specific products such as melons, berries, and leafy greens.

You should also ask if the employees are instructed in proper hand-washing procedures and if they have proper bathroom and dining facilities.

You can also ask how pesticides are being monitored.

In the case of organic produce, you can even ask the certifying agency or organization how things are being handled on a specific farm.

Gombas told Food Safety News that while it’s helpful to “know your farmer,” it’s even more important to know what sort of agricultural practices the farmer follows.

When he shops at farmers markets, he asks farmers he’s thinking of buying from about their agricultural practices.  “Smaller growers can have good food safety programs in place,” he said. “Ask them about them.”

But he also pointed out that food products can get contaminated every step of the way in the supply chain, which brings us full circle back to you, the consumer.

When it comes to raw produce, Gombas had this “mantra” to offer:  “Clean, chill and separate.”


Photo of FDA Commissioner Margaret Hamburg and United Fresh Senior Vice President of Food Safety and Technology David Gombas by Mike Steelman. Used with permission.