Sometimes the citrus you buy will have a hint of green on the outside. Even so, there is no reason to doubt the ripeness of Florida citrus, which is never picked unless it is perfectly ripe.
The greenish tinge is caused in two ways: Temperature is one controlling factor in the appearance of citrus. Warm days and cool nights are necessary for the fruit to turn a bright color. But sometimes the nights remain warm, depriving the crop of the cool temperatures that contribute to the orange or yellow color. As the fruit ripens, it remains slightly green on the outside, while developing perfectly on the inside.
The second factor is a natural process called "regreening." In the spring, trees have an extra supply of chlorophyll to help form the new fruit. The trees can bear both ripe fruit and blossoms at the same time. As the chlorophyll shoots up to the new growth, it is also absorbed by the skin of the ripe fruit, giving it an extra dose of green. Despite its greenish skin, the mature fruit is still luscious and delicious on the inside.
Storage: Fresh Florida citrus will last much longer under refrigeration. Temperatures from 35 degrees Fahrenheit to 50 degrees Fahrenheit are best. For grapefruit, a temperature between 45 degrees Fahrenheit and 48 degrees Fahrenheit is recommended. Citrus can be stored unrefrigerated in a cool, dry place for four to five days.
Plastic bags or film-wrapped trays should not be used for storing citrus. When airtight, drops of moisture may form between the film and the citrus peel, promoting mold growth.