Black Spots Inside Sweet Potato: Is It Safe to Eat?

If you’ve ever cut open a sweet potato and found that it has black spots on the insides, you might have wondered whether it’s okay to eat. What causes brown spots and are they edible, or do they need to be avoided?

Brown patches inside a sweet potato may be caused by bruising. Although they are hard, sweet potatoes aren’t impervious to bumps and knocks. They may also get small amounts of mold inside, which isn’t safe to eat, although you might be able to cut it out in some cases.

Why Do Sweet Potatoes Get Black Spots?

sweet potato

Often, a black spot on a sweet potato will be caused by bruising, possibly because of being dropped or knocked against another vegetable, either during transit or storage, or when you take the potato home from the store. You might not think of sweet potatoes as something that would bruise easily, but bruises can occur.

Black spots could also be caused by the following:

  • Black mold getting into the potato from damage to the skin
  • Cooking, which sometimes produces mysterious black spots where none previously existed

Let’s look at each of these possible explanations in more detail, and explore whether the sweet potato should be safe to eat or not.

Black Spots Caused By Bruising

If your sweet potato has been bumped by another vegetable or by a hard surface, it is surprisingly likely to bruise. Although sweet potatoes are a lot tougher than some vegetables, they are still prone to bruising when they get knocked about.

This is because the impact will damage the cell walls inside the vegetable, and this will cause the chemicals within those walls to leak out. When they mix with each and with oxygen, they often turn brown or black as a result.

This can lead to black spots inside the potato, and you might also find that the flesh is softer and mushier in that area. However, it should still be perfectly safe to eat. Many people choose to cut off larger black spots, as their texture and flavor may not be particularly good.

Simply use a clean knife to chop the affected part off and discard it. You can eat bruised areas without any risk if you prefer, but you may find that they aren’t as enjoyable.

Black Mold Spots

Sometimes, black spots in a sweet potato are the result of it turning moldy. This is more concerning and you should be aware of the risks – a moldy sweet potato could give you food poisoning. It may also make the potato taste unpleasant, potentially ruining the whole meal.

Generally, mold spots will only occur where the skin of the sweet potato has been broken. Usually, the skin does an excellent job of keeping mold and bacteria out of the potato, even when the potato has been bruised. However, if the skin breaks, mold spores can get into the potato. They will spread through any damaged areas with surprising speed.

If you are concerned about a black spot inside the sweet potato, check the outside area for damage. If the skin wasn’t broken, you may just be dealing with bruising. You should smell the potato for any hint of decay, and also gently poke the affected area. Rot often runs deep through the potato.

If the area feels slimy, sticky, or very mushy, it has likely been attacked by black mold. Very small areas can usually be safely cut out of the potato and the rest can be used, but large areas indicate that the whole potato has started to go off. Throw it away in this case, rather than trying to use it in foods. Even if it doesn’t make you sick, it will taste bad.

Black Spots That Appear During Cooking

Sometimes, black spots will appear after you have cut the potato and started boiling it, which can be both baffling and off-putting. These blackened areas can be large and they often surprise people because they aren’t there when the potato is cut open.

The explanation for this blackness appearing is fairly straightforward. Sweet potatoes contain a lot of phenolic compounds, and one of these is known as chlorogenic acid. This reacts with oxygen absorbed from the cooking water and surrounding air, and with iron from the potatoes. The reaction produces dark flesh, and sometimes a lot of it.

Fortunately, this will not make the potatoes unsafe to eat or change their texture or flavor. It simply does not look particularly appealing, which sometimes makes people worry that the potatoes aren’t safe to eat. Fortunately, they should be fine, and if you prefer, you can cut off dark areas and discard them.

How Do You Store Sweet Potatoes?

It’s important to choose good, fresh sweet potatoes at the store, and to check their skins for signs of damage. Don’t buy sweet potatoes with big, dark areas on the surface, or any with damaged skins. These will not keep well.

Once you get the potatoes home, place them in a cool, dry spot with plenty of ventilation. Basements are often a good place to keep them, but a suitable box at the bottom of your pantry can also work well. Don’t keep whole sweet potatoes in the fridge, as they don’t need to be chilled.

Once a sweet potato has been cut up, however, you should place the pieces in an airtight container and put them in the fridge until you are ready to use them. Don’t store a cut sweet potato at room temperature, because it will quickly begin to develop mold and go off. All cut sweet potatoes should be put in the fridge as soon as possible.


If you find a few little black spots in your sweet potato, it’s usually okay to cut these out and use the rest of the flesh. However, if the potato has large black patches or if it is mushy or smells bad, you may need to throw it away, because it has been contaminated by mold.

Hey there! My name is Alex and I've been vegan for over five years! I've set up this blog because I'm passionate about veganism and living a more spiritually fulfilling life where I'm more in tune with nature. Hopefully, I can use Vegan Foundry as a channel to help you out on your own journey!