"A group of environmental and public health groups sued the U.S. Food and Drug Administration on Thursday, seeking to set aside the agency's approvals for feed additives containing ractopamine that are used to boost the weight of cattle and pigs.

The groups, in two related lawsuits filed in federal court, claim that the FDA failed to adequately assess environmental and health issues related to ractopamine.

Used for more than a decade in the U.S. agriculture industry to build lean muscle instead of fat, ractopamine, a beta-agonist, has been barred by some major meat importers around the globe, including China. China last year began requiring third-party verification that U.S. pork products were ractopamine-free. Beta-agonists boost an animal's ability to convert calories to marketable meat."

P.J. Huffstutter reports for Reuters November 6, 2014. [2]