If Your Potato Smells Like This, Don't Eat It, Experts Warn

If your potatoes smell bitter, don't eat them, experts say.

Potatoes are members of the nightshade family, which naturally contain the toxin solanine. Though experts point out that you can consume a small amount of solanine without having any adverse reaction, potatoes and other tubers can develop the toxin in abundance when stored improperly.

Thankfully there are two common signs that a potato has developed dangerous levels of solanine: they can give off a bitter smell, and their skin may turn a shade of green. "While the green itself is harmless chlorophyll, the green color is an indicator of the presence of solanine," explains a report from Michigan State University (MSU). "Rotting potatoes give off a noxious solanine gas that can make a person unconscious if they've inhaled enough," their experts add.

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Too much solanine can wreak havoc on your health.

Consuming potatoes that have overproduced solanine can have serious health consequences. The toxin is known to "cause gastrointestinal distress, induce coma or even death within 24 hours of consumption," reports Smithsonian Magazine.

In fact, one case study recounts the story of 78 British schoolboys who abruptly became ill in 1979. "Symptoms included vomiting, diarrhea, abdominal pain and, in severe cases, depression of the central nervous system. Several patients were comatose with episodes of convulsive twitching and violent fits of fever," the study says. "In many patients, there were signs of peripheral circulatory collapse," the researchers note. It soon became apparent that the boys had all eaten boiled potatoes from the same bag, which had been sitting in improper storage since the prior school term. All of the students ultimately recovered, but not without enduring serious symptoms.

The problem is caused by insufficient storage.

According to MSU, the problem arises when potatoes are exposed to light for too long. Both natural and fluorescent light can provoke toxicity, so it's best to keep potatoes in a paper bag or cardboard box inside a cabinet, pantry, or root cellar that has no light exposure.

"Keep them in a cool, dark place, and avoid exposure to light during transport," says the Michigan State report. "If you find or buy green potatoes, throw them out. While removing the green and cooking them removes some of the solanine, it may not be enough to prevent illness," their experts advise.

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Storing them for too long can be dangerous, too.

Storing your potatoes in a dark space can help lengthen their shelf life, but experts say that keeping them anywhere for too long can pose serious health risks. "There have even been cases of people dying in their root cellars due to unbeknownst rotting potatoes," says the MSU report. "If there are a bunch of potatoes that have gone bad, make sure to properly ventilate the area before working to remove the bad potatoes."

When in doubt, experts recommend inspecting potatoes for signs of diminished quality. These include "mold, decay or eyes" growing on the skin, which can all indicate that a potato is past its prime. Keeping tabs on how long you've had them can also spare you some serious health woes. Most unrefrigerated potatoes will start going bad after just one to two weeks. Finally, as with all potential cases of food spoilage, be sure to follow this simple rule from the Centers for Disease Control and Prevention (CDC): "when in doubt, throw it out."

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