Beef producers are being asked to administer injections into a tightened injection site zone in an animal's neck. This new zone is a hand's width in front of the shoulder and several inches shorter than the previous zone (see blue area in diagram at right).

The tighter zone is a beef quality assurance measure to reduce greenish lesions showing up in retail cuts packaged in modified-atmosphere packaging (MAP). MAP is a combination of 80% oxygen and 20% carbon dioxide that is used to prolong bloom.

“We're finding a 15% to 20% incidence of greenish lesions in chuck steaks where MAP is being used,” says Dee Griffin, DVM, University of Nebraska.

Griffin says the greenish lesions are likely not new. They just hadn't been detected before the use of MAP. Another factor, he says, is that retailers are now using part of the chuck for steaks.

“Our work shows that one chuck muscle plays a major role in the problem,” Griffin states. “By tightening the injection site zone, this particular muscle is avoided, and incidence of lesions can be significantly reduced.”

Griffin adds that current research indicates no particular product or formulation is responsible for the greenish lesions.

“…Giving products subcutaneously when possible, tightening the old injection site zone and administering intramuscular injections at least a hand's width ahead of the shoulder will be a big step in addressing the problem,” he says.

To keep administration of products at least three inches apart, producers are also asked to administer vaccinations in both sides of an animal's neck.