If one berry is moldy, spores have traveled throughout the entire package. Use strawberries as soon as possible after harvest or purchase. Refrigerator storage does not improve the quality of fresh strawberries. Berries should not be left at room temperature for more than a few hours, because warm temperatures cause a browning effect in strawberries. The pigments that make strawberries red are heat-sensitive, and break apart and turn brown when exposed to heat.
Strawberries also lose vitamin C during browning, heating and cooking.
Store unwashed berries loosely covered with plastic wrap in the coldest part of your refrigerator for two to three days at most. Do not wash berries until ready to use. To wash, place berries in a colander and rinse under cold running water. Do not allow berries to sit in water as they will lose color and flavor. After washing, remove the green cap with a plastic-tipped vegetable peeler or paring knife without removing any of the fruit.