Chocolate is very sensitive to temperature and humidity.
Ideal storage temperatures are between 15 and 18°C (59 and 63°F), with a relative humidity of less than 50%.
Whitening or "blooming" effects can occur if chocolate is stored or served improperly but is not an indication of chocolate gone bad.
Chocolate is generally stored in a cool, dark place, away from other foods, as it can absorb different aromas. Ideally, chocolates are packed or wrapped, and placed in proper storage with the correct humidity and temperature.