Found this somewhere on the net:
It's probably fair to say that every omnivorous home cook has wondered at some point or another whether it's OK to refreeze that piece of steak after thawing it out and realizing it won't need to be made after all. The short answer? Yes, you can — but you may not want to.
According to the USDA, when raw meat is thawed in the refrigerator, it is safe to refreeze it without cooking. For this reason, it's perfectly all right to purchase, say, a previously frozen piece of salmon, and then put it in your freezer when you get home. But if you refreeze thawed poultry or meat, you will be compromising quality of taste and texture. Not only does meat lose water during the defrosting process, but refreezing it also creates ice crystals within the structure of the meat that alter its fibers, leaving an unfortunately dry cut of meat.
Of course, like all raw animal protein, the true safety of the product will depend on whether it's been properly handled. The best ways to defrost raw meat are in the refrigerator, in cold water, or in the microwave — not on a room-temperature kitchen counter.
