What to Watch for When Washing Vegetables, and How Do You Reduce Pesticide Residue?

The most effective way to wash vegetables is to scrub the surface by hand under cold running tap water to remove soil, pesticide residue and germs; soap or detergent should never be used, since a vegetable's porous surface absorbs these chemicals and rinsing doesn't fully remove them. For firm-skinned vegetables like potatoes, carrots or zucchini, a vegetable brush removes more residue than hand-scrubbing alone. Leafy vegetables release trapped soil more easily if left to soak in a bowl of water for 5-10 minutes before rinsing. Does a vinegar rinse really reduce residue? Soaking vegetables for 10-15 minutes in a mixture of 200 ml measure of vinegar per 1 liter of water removes slightly more surface residue than plain water alone, but it doesn't eliminate residue entirely. Vegetables soaked in vinegar water must be rinsed thoroughly afterward, or the smell and taste of vinegar will carry over. A baking-powder solution has a similar effect; 4 ml measure of baking powder per 1 liter of water shifts the surface pH and helps dissolve some of the residue. How do you clean leafy greens more thoroughly? With lettuce, spinach and arugula, soil gets trapped between the leaves and around the base of the stems, so separating the leaves and swishing them in a large bowl of water works better than a quick rinse under the tap. Repeat with fresh water — usually two or three changes — until the water stays clear. Leafy greens that won't be used right away should be dried thoroughly first; wet leaves spoil faster in the fridge and don't keep as long. Leafless but thin-skinned vegetables like cucumbers need similar care; the waxy layer on the skin is sometimes natural and sometimes a coating applied afterward to extend shelf life. When it's noticeable, and the vegetable won't be peeled, it's worth scrubbing a little longer with a brush. Which vegetables tend to carry more pesticide residue? Vegetables with thin, porous skin, like peppers and cucumbers, tend to hold onto more residue than thick-skinned ones like zucchini and eggplants, because pesticide can penetrate deeper into a thin skin. For vegetables you can peel, peeling removes noticeably more residue than washing alone — though you also lose some of the fiber and vitamins that sit in the skin. How much pesticide residue affects health in the long run depends on the type and amount of pesticide used; buying vegetables from a variety of sources reduces how much you're exposed to any single grower's residue levels over time. How should washed vegetables be stored? Washed vegetables should be dried thoroughly before going in the fridge; leftover moisture speeds up mold growth in a sealed container or bag. Leafy vegetables wrapped in paper towel stay fresh several days longer than ones left uncovered, since the towel absorbs the excess moisture. Unwashed vegetables should be kept in a separate compartment from washed ones; otherwise soil from an unwashed vegetable can transfer onto one that's already been cleaned. The bowl, brush and countertop used for washing vegetables need regular cleaning too; soil and moisture that build up on these surfaces can transfer back onto clean vegetables the next time around.