While fresh fruit provides valuable vitamins and nutrients, you shouldn't eat it when it's spoiled -- not only does it not taste as good, but it can make you ill. The signs of spoiling on some types of fruit are obvious at a glance, but with other fruit, you may need to take a more hands-on approach. The look, feel and smell of your fruit can help you identify whether it has begun to spoil, and whether it is safe to eat or should simply be thrown away.
Check the expiration date on the package. Apples, for example, may have the expiration date printed on the bag.
Look for mold on the outside of your fruit. For fruit without rinds, like berries, this indicates that it's spoiled. For citrus fruit with a rind, like oranges and grapefruit, this means that you must peel them to determine if they're spoiled. If the mold has spread to the flesh of the fruit, or if you can poke your finger through the rind, throw the fruit away. If it's only on the rind, you can peel the fruit and eat it.
Inspect the skin of fruits like grapes, apples, peaches and cherries. If it is wrinkled and/or peeling, it has begun to spoil. If it is smooth, it is still good.
Feel and squeeze your fruit. Many fruits like melons and pineapples should be firm when you eat them, as they get softer with age. Once they are squishy, soft and malleable, they should be thrown away -- they also tend to develop a foul odor at the same time.