While the US Food & Drug Administration (FDA) allows for the use of leanness-enhancing food additive zilpaterol in animals to be sold for slaughter up to a specified amount, treatment of the drug in the US and abroad has been in constant flux during the past few months. Zilpaterol is a beta-agonist, a feed additive that can add as much as 30 pounds of saleable meat to an animal in the weeks before slaughter. Merck suspended its sales of Zilmax, the most common of zilpaterol-based drugs, in mid-August. This suspension came quickly on the heels of an announcement by the largest meat processor in the US, Tyson, stating that it would no longer accept Zilmax-fed beef.

Despite FDA's approval of the drug, there is zero tolerance for the food additive in much of Asia and Europe, due to concerns about potential side effects. In early October, South Korea suspended all US beef imports after detecting zilpaterol, which is currently banned by South Korea, in meat supplied by a US company. However, South Korea recently announced its intention to end its ban on zilpaterol early in 2014, reopening the door to beef imports from the US. Similarly, toward the end of last month, Taiwan detected zilpaterol in a shipment of US beef, leading it to destroy the entire import. However, in 2012 the US beef industry and Taiwanese regulatory agencies had a similar conflict over use of ractopamine, another growth-enhancing drug, which concluded with Taiwan lifting its ban on the same.

Zilpaterol is also the subject of a lawsuit against the FDA in the US District Court for the District of Columbia against the FDA. The suit, filed by the Animal Legal Defense Fund (ALDF) and the non-profit Center for Food Safety (CFS) against the FDA alleges that the agency withheld records related to its approval of the additive. The plaintiff's complaint for declaratory and injunctive relief can be found here. Norton Rose Fulbright will continue to monitor the conflicts occurring over the use of zilpaterol, both domestically and abroad.