You've probably seen a Snickers, Milky Way, or Hershey's bar with a strange chunk of white dust or an off-colored part. You must have worried if it was safe to eat.
It turns out that the dusty appearance is caused by a process known as "chocolate bloom." Chocolate bloom is explained by basic food science.
When chocolate is left in a warm, the fat separates from the other ingredients as it cools and reformed. The fat then forms that white, dusty film as it rises to the surface.
Sugar crystallizes due to excess moisture in a similar process known as sugar chocolate bloom. When this happens, the top of the candy bar will often have a speckled appearance.
To put it briefly, yes, it is safe. It's possible the flavor will be off, but you can still eat it.
You can use blooming chocolate in baking if you don't feel comfortable eating it but don't want to waste the candy.
Mix pieces of chocolate bars into brownies, drop them into cookies, or use crushed chocolate bars as a garnish for chocolate-covered pretzels.