There are key indicators that are different ways of telling if an onion has gone bad. These can be used to evaluate whether your onion should be eaten. These are the best ways to tell if an onion is bad. By doing a careful evaluation of an onion using these factors, you will be able to have a good knowledge of knowing whether your onion is bad or whether it is safe to eat.
For longest shelf life, your whole onions should be stored in a cool dry location such as refrigerator or cellar.