Potatoes are a staple in most households and when kept in a dark, cool place, it seems like they last forever. Unfortunately, they do start to rot after a while even in the best storage circumstances, and when they do, it's hard not to notice. Not only will a bad potato look bad, the smell of rotting potato is similar to of a dead animal. Also, it's important to check the sack of potato periodically in case one has started to rot, because the gases it emits will quickly cause the rest of the potatoes to go bad as well.
Smell the potato. This will be the most obvious way to determine if the potato has gone bad. A rotten potato will have a strong, vile smell to it that you can't miss. Fresh potatoes will have an earthy, starchy smell to them.
Look at the potato. A fresh should look smooth and not have any signs of decay. A shrivelled-looking potato is a sign of a bad potato. Also, if the potato is turning green and the eyes are beginning to sprout, discard the potato because it may contain toxins associated with sprouting.
Feel the potato.The potato should be firm to the touch and feel smooth. If the potato feels soft and spongy, and wrinkled throw it away.
When selecting potatoes at the store, avoid buying the one already in a bag because you can't inspect them to see if any have begun to go bad. Instead, select the potatoes individually so that you can inspect each one.
Get rid of a pad potato immediately, as they will attract fleas, flies, ants and other insects into your home.