The black spots on sweet potatoes are a sign of decay, caused by fungi that have invaded the potato. These spots can appear anywhere on the potato’s surface and will often be accompanied by a soft, mushy texture. If you find black spots on your sweet potato, it is best to discard it as it can be unsafe to eat. To prevent sweet potatoes from developing black spots, it is important to store them properly. Sweet potatoes should be kept in a cool, dark place with good air circulation and away from sources of moisture. It is also important to inspect them regularly for any signs of decay or damage. If you notice any discoloration or softness, discard the potato immediately. In addition to proper storage techniques, choosing quality sweet potatoes is also essential for avoiding spoilage. Look for firm potatoes with smooth skin and no obvious damage or bruises.