We have all seen it, the red liquid that comes with raw meat. Often it can be found in the beef packaging its self before the meat is cooked, or once you cut into that perfectly cooked medium rare steak, there is red liquid on the pate. It is also often why people cook their steaks closer to well done, so that the 'blood' is reabsorbed back into the meat.
But what is it actually? No, its not blood. Its a solution that is called "purge" or "weep" and most often its mistaken for being blood. Its actually a mix of water and myoglobin, a protein that delivers oxygen to the animals muscle.
Once the protein is exposed to air, or the meat is cut is when it then turns red. Its also the iron that is in the meat that turns the myoglobin red. If it truly was blood, there would be the same blood in white meat packages too.
Myoglobin is also what is responsible for turning beef brown, and brown meat does not always mean it is bad meat. When myoglobin molecules naturally oxidize, it will turn the beef brown. Just be sure to cook it right, and cook it right away.
So, eat that juicy steak to however your preferred done-ness, and be assured that there is no blood involved.