Washing fruits and vegetables can help remove residual pesticides, germs, and dirt. With fresh lettuce straight from the field, the need to wash it is immediately obvious—after all, no one likes crunching on sand between their teeth. All types of fruits and vegetables should be washed whole before eating. Only then should any spoiled or wilted parts be removed. Don’t cut them up beforehand either, or vitamins and nutrients will be lost during washing. As a general rule, wash and cut them just before eating; this helps preserve their natural protective layer and keep the bacterial count low.

Sturdy produce, such as potatoes or carrots, can be washed with water and a vegetable brush. Delicate produce, such as lettuce or raspberries, should be rinsed in plenty of standing water but not soaked for too long. The stream of water from the faucet doesn’t always reach every part of the surface. If you want to save water and wash thoroughly, it’s better to wash in a bowl and use the leftover water, for example, to water your plants. Depending on the sturdiness of the fruit or vegetable, you can then dry it off or pat it dry. Both methods provide additional cleaning of the surface.

There are foods where opinions differ on the topic of washing, most notably mushrooms. Many cookbooks state that mushrooms should only be cleaned with a soft brush. The main argument is that, since mushrooms do not have a hard skin, they would absorb water and then lose their flavor. In principle, most types of mushrooms have a high water content, so additional water absorption is hardly possible. Therefore, there’s no reason not to briefly rinse commercially available cultivated mushrooms under running water or clean them with a damp cloth. Brushing off mushrooms you’ve picked yourself helps remove large clumps of dirt, such as sand or pine needles. Whether to wash them further should depend on the mushroom’s structure.

When it comes to washing, people often forget about fruits that need to be peeled, such as bananas, mangoes, oranges, and tangerines. The surfaces of these fruits also contain residues of pesticides and other treatment chemicals. When peeling, these residues end up on our hands and from there onto the peeled fruit. Therefore, the same rule applies here: wash first, then peel, then eat—and don’t forget to wash your hands.  

The extent to which baking soda or vinegar can improve cleaning and reduce germs has been the subject of several scientific studies. For example, in a 2017 study by American scientists, three different cleaning methods were tested. Using apples, they tested whether washing with tap water, a commercially available chlorine bleach, or baking soda (sodium bicarbonate) was most effective. The results showed that even tap water alone provides good cleaning performance. Cleaning with baking soda was particularly effective at reducing a preservative (thiabendazole) and a broad-spectrum insecticide. Regular baking soda can help remove significantly more contaminants, but only if the fruit is soaked in a (weak) baking soda solution for a quarter of an hour. Ultimately, adding baking soda or vinegar can negatively affect the taste and texture of certain fruits and vegetables. The extent to which this is considered a problem is a matter of personal preference.

In studies, organically grown products have performed significantly better in terms of pesticide residue levels. However, this does not mean they are germ-free.  Organic products are also exposed to air pollution, and contaminants can end up on them—for example, through rain. Furthermore, organic farming is often not confined to a single region, so even small amounts of plant protection products can be carried over from neighboring fields. Natural bacteria in the soil also end up on organically grown fruits and vegetables during cultivation. Therefore, even organically grown produce should be washed thoroughly before consumption.