2. Lack of Oxygen Inside the Potato
If a potato is stored in an environment where it doesn’t get enough oxygen, it can develop a condition known as blackheart, where the center of the potato turns black. However, internal black spot is a bit different — it’s less severe and typically appears as ring-like spots rather than completely darkened centers. It’s often a result of pressure-related bruising, though both conditions are linked to the potato’s exposure to low oxygen levels during storage.
3. Temperature Stress
Potatoes have very specific temperature requirements. If they are stored in the refrigerator or exposed to extreme temperature fluctuations, it can affect the potato’s internal chemistry, causing dark spots to form. Potatoes prefer cool (but not cold) temperatures. Storing them in a fridge can turn the starches inside into sugar, which might result in the formation of internal black spots or rings.
4. Oxidation of Natural Vascular Tissue
In some cases, the black rings you see in a potato may be the result of natural oxidation. The vascular tissue, which is the network of veins that runs through the potato, can darken over time when exposed to air, especially after the potato is cut. This isn’t a sign of spoilage — it’s just the normal process of oxidation.
Is It Safe to Eat Potatoes with a Black Spot Inside?
Generally speaking, yes, potatoes with internal black spots are safe to eat. The spots are not toxic and don’t indicate any harmful fungus or bacteria. However, the affected areas might have a slightly drier texture or a bit of bitterness, so many people prefer to cut those parts out before cooking. If the rest of the potato looks and smells fine, it’s likely safe to eat.
