Margaret Barth, author of "Microbiological Spoilage of Fruits and Vegetables," estimates that of all the product that is grown in the United States, 20 percent will be lost to spoilage. One of the chief means of reducing this spoilage is refrigeration. Some fruit benefits from refrigeration. Some, however, is spoiled if you put it in the refrigerator too soon.
Some fruits ripen after they are picked. Some don't. Strawberries, cherries and grapes ripen on the plant. Once you pick them, they may get softer due to the natural deterioration of plant matter, but they will never get any sweeter. In other words, once picked, these fruits are as ripe as they will ever get. Fruits that don't ripen after picking should be refrigerated immediately. Other fruits that fall into this category are apples, blueberries, raspberries, tangerines, oranges, limes and blackberries.
Ripening after Picking
Other fruits continue to ripen after picking. In these fruits ethylene gas is part of a ripening signal. If the fruit is left on the plant long enough, the plant will send the signal. But the signal can also be triggered by a wound to the plant. The wound made when the fruit is cut from the plant can actually trigger ripening. These kinds of fruits--avocados, bananas, pears, plums and tomatoes--will stop ripening if you put them in the refrigerator. For best quality, ripen them at room temperature in a brown paper bag that traps the ethylene gas. When the fruit is fully ripe, you can store it in the refrigerator to stop it from over-ripening or spoiling.
Refrigeration and Spoilage
All fruit can spoil. Ripe fruit spoils more quickly than unripe fruit. One of the reasons fruit spoils is bacteria, mold and fungus. If you have ever forgotten about a peach only to find it covered in blue or green mold, you are familiar with this kind of spoilage. Refrigeration slows the growth of these microbes. In doing so it buys you a little bit of time between the time your fruit is fully ripe and the time it starts to deteriorate.
Fresh cut fruit always requires refrigeration. Whether the fruit was cut before you bought it or whether you cut it up, that fruit needs to be refrigerated. Soft fruits that have been cut up, fruits like mangos or melons, typically have a shelf life of two days or less even if they are refrigerated. Fruits containing more acid or harder fruits have a slightly longer shelf life. Anytime you cut open a fruit, you accelerate the ripening process and expose that fruit to bacteria, mold and fungus. For both food safety reasons and food quality reasons, keep cut fruit in the refrigerator.