Ground beef is a very versatile beef product with a bright red color. Meat in the middle and bottom of the package may not be as bright red as the outside because of a lack of oxygen. Lack of oxygen has no affect on the quality of the meat.
Varieties differ as a result of their fat content as well as the cut of the meat. In some areas, different varieties vary by fat content only.
Ground Beef: 73-75% lean
Ground Chuck: 81% lean (from the chuck or shoulder area)
Ground Round: 85% (from the round)
Ground Sirloin: 86%-92% lean (from the sirloin)