What's The White Ooze On Sweet Potatoes?

It's not what you think.

sliced sweet potatoes
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Bright orange and full of beta-carotene, sweet potatoes make a wonderfully tasty addition to any diet. Cubed in soups, added to salads, or simply by themselves, this complex carbohydrate is a great source of energy for your body.

But there’s just one problem: If you cut into your sweet potato and see it seeping a milky white substance, you may change your mind about your meal.

What Is That White Ooze on My Sweet Potatoes?

A milky substance on your sliced sweet potato doesn’t mean that your spud is rotten or spoiled. The ooze is actually referred to as "sap." It is made up of sugar and starch combined with the moisture found in the vegetable, and it escapes out of the damage made from the knife.

The sap really equals the sweetness. If it’s pouring out of your potato, that means it’s a sweet and delicious vegetable.

Do Some Potatoes Ooze More?

Sweet potatoes dry out as they get older, so finding a ton of white liquid seeping from your cut areas just means that the potato is nice and fresh. Basically, the older potatoes will be much dryer and less sweeter—and also less likely to have sap.

Does the Ooze Make You Itch?


Some people report experiencing irritated skin after handling a sweet potato that has the milky substance on it. If you experience itching, it’s a good idea to avoid eating the potato at all. Though rare, this irritation may signal an allergy that results in worse problems after consuming the vegetable. Other symptoms, like itchy eyes, sneezing, sore throat, or stuffy nose might occur while it’s being handled. Allergies to raw potatoes, rather than cooked ones, are more common, which is why handling the sap seems to cause an immediate reaction.

People who are allergic to other vegetables in the nightshade family, like eggplants, peppers or tomatoes, might also be sensitive to sweet potatoes. Nightshades also include cayenne, paprika and tobacco.

Bottom line: The best rule of thumb is that if the ooze makes you itch, don’t eat the sweet potato, and call your doctor. They can perform allergy tests to learn more.

Tip

Really don’t like to see the ooze on sweet potatoes? Bake your potato first, before you cut it.

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