South Korea has suspended some U.S. beef imports after detecting the cattle feed additive zipaterol in meat supplied by a unit of JBS USA. South Korea's food ministry said it had halted imports from a work site at Swift Beef Co.  and asked the United States to investigate the cause of the contamination which was found in 22 tons of meat, reports Reuters.

The ministry said it had strengthened scrutiny of U.S. beef since Taiwan had also detected zilpaterol in U.S. beef last month. Taiwan's Food and Drug Administration said it had asked the importer of the contaminated cargo to destroy or send back the meat.

"As of now, we don't clearly know when we will complete examining U.S. beef from Swift Beef Co. We plan to inspect all of the meat from the company," said Ahn Man-ho, vice spokesman for the food ministry in Seoul. "If we find further zilpaterol in U.S. beef or in any other meat, we will take a similar action."

Reuters reported that a spokesman for JBS or the USDA could not be reached for comment.

Zilpaterol is a beta agonist, a feed additive that adds weight to an animal before harvesting. Beta agonists have been in the news because Tyson Foods announced it would no longer purchased cattle finished with Zilmax, another beta agonist, after noticing some cattle that were fed the additive had trouble walking. Merck & Co., which manufactured the drug, announced it would suspend sales while carrying out an audit on how the product was being used.

Source: Reuters