Our Definitive Guide to Washing Vegetables
There is a bag of fresh vegetables from the market in the kitchen. Roots, leaves, and crunchy stems means salads, sides, and entrées to come. But what is the first step in safe preparation? Should all vegetables be washed? And what's the best way to wash fresh produce? First, remember that the chance of becoming ill from eating fresh vegetables is low. Most people consume these healthy foods with no ill effect. That said, people with compromised immune systems, as well as the elderly, are more at risk.
The most reliable method of destroying foodborne pathogens is heat: If you want to be certain that dangerous microbes are not present, wash, and then cook your vegetables. Experts recommend that any fresh produce, whether it's organically grown, purchased from a supermarket or a farmers' market, or even from your own garden, should be washed. Microscopic pathogens hide in plain sight. Bacteria, viruses, and parasites are the tiny culprits that cause foodborne illness.
Bacteria are everywhere and are essential for life (and sourdough!). A million could fit on the head of a pin. In terms of food safety, undesirable bacteria come mostly from unwashed hands. They may also be spread through dirty water (in irrigation or, ironically, triple washing), livestock or wild animal feces, coughing, sneezing, insects, rodents, or dirty utensils. Viruses are tinier than bacteria. Unlike bacteria, viruses do not reproduce in food; it only serves as their vehicle to a human host. The presence of a virus on fresh produce is usually a sign of contamination due to poor hygiene: like not washing hands thoroughly after using the toilet, or coughing, and before handling food.
Parasites are rare in vegetables (raw meat and fish are the more common vectors). But parasites can be transmitted by poor hygiene (wash hands after cleaning the litter box), or via wild foods—like mushrooms collected where animal scat is present, or watercress from streams where liver fluke occurs. When in doubt, cook vegetables thoroughly. Washing will not help.
How to Wash Vegetables
Before washing vegetables, wash your hands. Soaking or swirling vegetables in a bowl of water is ineffective and may even spread a contaminant. Vegetables must first be scrubbed, and then rinsed off in running water. If you intend to peel the vegetables later, wash them with soap. Soap also destroys waxy coatings that bacteria enjoy sticking to. If you intend eating the vegetables with skins on, some soap residue may remain, and the FDA has no data on the effects of consuming it. And special washes marketed for fresh produce have not been evaluated for their effectiveness. If in doubt, peel before eating.
Use a clean scrubbing brush to clean your vegetables, the disinfect it in the dishwasher after. After you're done scrubbing, rinse washed vegetables under running water. Dry thoroughly with freshly cleaned kitchen towels or paper towels.
Which Vegetables Should Be Washed?
Vegetables with skins should always be washed. These include roots and tubers like beets, carrots, turnips, parsnips, celeriac, radishes, rutabagas, potatoes, and sweet potatoes. Fruits (that are often confused for vegetables) including cucumbers, peppers, eggplants, tomatoes, and summer and winter squash also fall into this category. Luckily, they all come with handy built-in wrappers (their skin) and are the easiest to wash effectively.
In the flower and bud family, you'll want to wash globe artichokes, broccolini, broccoli, and cauliflower—but these are all vegetables that are hard to wash perfectly. If you're cooking them, there's nothing to worry about—harmful bacteria that you missed during the washing process will cook off. If you want to enjoy the crucifers raw we recommend peeling and eating broccoli's thick, washed stems, or the crunchy core of a cauliflower.
Beans and peas in shells should be placed in a strainer for cleaning; rub them well while rinsing under running water. Certain vegetables in the onion family do not lend themselves to washing. Case in point? Washing onions and garlic with dry skins is not practical, but do peel them and wash your knife and hands after peeling, and before chopping or slicing. Soak leeks to get rid of lurking sand, but then rinse them under running water. Ditto with scallions.
For leafy greens like cabbages and Brussels sprouts, be sure to remove their outer leaves before washing. Swiss chard, chicories, dandelions, spinach, all the Asian greens, beet greens, lettuces, and arugula are impossible to wash 100 percent effectively. In fact, washing may even spread a contaminant like E.coli around. Cooking-heat will destroy any pathogen. Cooked greens are still very healthy and are sometimes more nutritious than raw (think spinach). The bad news is that we love raw salad, and people get sick more often from eating contaminated lettuce and other salad greens because they are rarely cooked before being eaten.
Are pre-washed, bagged greens safer? No. Pathogens may have been present in their washing water, or on hands when they were bagged. The only way to eliminate any chance of foodborne illness from leaves is to cook them. But if you love salad as much as we do, you may prefer to rinse them under running water, take a deep breathe, and trust the statistics. The chances are excellent that they will do you more good than harm.