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Fried, baked, or scalloped: There isn’t a potato dish I don’t adore. The only time potatoes don’t make me happy? When I find a green spot on one of them as I’m preparing dinner, and I have no idea whether it’s still OK to eat.
Honestly, I have so many questions. Can you cut off the green part and hope for the best? Or does the green tinge mean the potato has gone bad and it should be thrown away? To find out, I talked to a food safety expert. Read on to learn why potatoes turn green in the first place, and whether they're safe to eat.
Why Do Potatoes Turn Green?
Potatoes are a root vegetable that grow underground, so they’re not exposed to very much light. According to Kali Kniel, PhD, professor of microbial food safety at the University of Delaware, light exposure can increase the concentration of chlorophyll inside potatoes, causing them to turn green on the skin.
In potatoes, the green hue can also indicate an increase in a natural glycoalkaloid compound called solanine. “This is one reason it’s recommended that potatoes are stored in the dark and away from light,” says Kniel.
In nature, these compounds play an important role, helping protect plants from fungi and insects. But when you eat a potato that’s developed these protective compounds, you may notice a bitter taste—which is reason enough to think twice about a green potato for dinner.
Is It Safe to Eat Green Potatoes?
Yes, but with a few caveats. The U.S. Department of Agriculture recommends not eating the green part of potatoes, but you don’t have to worry about tossing the entire thing. Instead, Kniel recommends just cutting off the green part and proceeding with your recipe. (The potato will taste better that way, anyway.)
Theoretically, too much of the green skin could make you sick. Kniel says consuming high amounts of glycoalkaloids can lead to gastrointestinal symptoms such as nausea, vomiting, and diarrhea—but that’s a really unlikely scenario, because Kniel says you’d have to eat a LOT of green potatoes for that to happen.
The European Food Safety Authority (EFSA) states that 1 milligram per kilogram of body weight per day is the lowest dose at which undesired effects are observed. So if you weigh 175 pounds, or almost 80 kg, you’d have to eat 80 mg of glycoalkaloids a day (that's a lot) to notice ANY bothersome GI symptoms—but probably way more to get really sick.
Plus, you can protect yourself from the potential negative effects. “The risk of consuming solanine can be reduced simply by peeling the potatoes, and then it is even further reduced by cooking,” says Kniel.
How To Properly Store Potatoes
To keep your potatoes from turning green—and to help them last longer—Kniel recommends storing them in a cool, dry area that isn’t exposed to light, like a pantry shelf or a storage area in your garage or basement.
Washing them prior to storage can promote microbial growth and increase your risk of getting sick from potatoes. Instead, just wipe them off with a cloth or paper towel, and wash them immediately before preparing them—making sure to check for any pesky green areas in the process.