According to the Australian Institute of Food Safety, your refrigerator should be 5°C or colder. At this temperature, any bacteria present on or in food can only develop very slowly, so keeping food this cold is a good way to prevent cooked or prepared food from spoiling for as long as possible. (Freezing food virtually stops bacterial growth, but it also significantly changes the texture of many foods.) Still, keeping some foods that cold isn't a good idea or even necessary. Cold can stop the ripening process of fruits, and in a few cases, the temperature in your refrigerator can break down the cell walls in fruits or vegetables, turning them mealy. Many fruits and veggies keep best when kept cool and prefer warmer rather than colder conditions.

Important note: The following guidelines for vegetables and fruits apply to whole, intact items. Once they get overripe or develop even one soft spot, or if the skin is broken, they need to be eaten, cooked, or refrigerated/frozen ASAP.