The chocolate is safe to eat. This usually happens when the chocolate is kept at a temperature of 70-75 degrees Fahrenheit.
Moisture condenses on the surface and sugar from the chocolate dissolves in it.
As the moisture evaporates, it leaves behind a crust of white sugar crystals. One way to avoid white discoloration is to wrap and store chocolate carefully in a cool place but not in the refrigerator, says Struempler. White chocolate is a mix of milk solids, cocoa butter and sugar and contains no cocoa solids. Because of its hue, consumers will not see fat or sugar bloom. However, Struempler warns that white chocolate turns rancid more quickly than regular chocolate.