As I mentioned just below, there are two kinds of chocolate bloom: fat bloom and sugar bloom. Neither are catastrophic to your chocolate supply (just melt the stuff), and both can be prevented to one degree or another.
First, fat bloom. If you’re applying melted chocolate as a glaze or as a coating on some home made truffles, all you need to do to inhibit streaks is to put the finished products into the refrigerator. The quick burst of cool essentially freezes the cocoa butter molecules in place before they have a chance to congregate on the surface of the chocolate. Note that the effect isn’t necessarily permanent once the chocolate is removed from the refrigerator, so you might want to keep your whatever-the-are’s chilled until just before serving. The other option is to of course to temper the chocolate which, in addition to bloom-proofing your coating will also give it a nice firm texture and glossy shine.
People who freeze chocolate, as opposed to those who just man up and eat it, also have problems with fat bloom. Sugar bloom too. The reason is that cold temperatures accelerate crystallization of both substances. The process can’t be stopped completely but it can be reduced by a.) wrapping up your chocolate tightly and then b.) lowering its temperature in stages instead of all at once. Place the chocolate in a cool room in your house, then the next day in the refrigerator and the next in the freezer, as far back in the freezer as you can. These principles apply to those who simply want to refrigerate their chocolate, though there’re really no reason to do that unless your house is getting awfully hot on the inside. Thanks, Jey!