In people who have aplastic anemia, the body doesn't make enough red blood cells, white blood cells, and platelets. This is because the bone marrow's stem cells are damaged. (Aplastic anemia also is called bone marrow failure.) Many diseases, conditions, and factors can damage the stem cells.
The best way to safely thaw ground beef is in the refrigerator. Keeping meat cold while it is defrosting is essential to prevent growth of bacteria. Cook or refreeze it within 1 or 2 days. To defrost ground beef more rapidly, you can defrost in the microwave oven or in cold water. ...
Turns out it's not entirely true. If something is frozen and thawed, it can be refrozen -- as long as it was defrosted safely. So if you started to defrost a roast in the fridge and then realized you didn't need it, you could put it back in the freezer.