UPDATE 1-S.Korea suspends some U.S. beef imports over controversial feed additive
* South Korea says detects zilpaterol in 22 tonnes of U.S. beef
* Says halts some U.S. beef imports from unit of JBS USA
* Seoul has asked U.S. to investigate cause of contamination
SEOUL, Oct 9 (Reuters) - South Korea said it has suspended some U.S. beef imports after detecting the controversial growth enhancer in cattle, Zilpaterol, in 22 tonnes of beef supplied by a work site from a unit of meat producer JBS USA.
Zilpaterol is a beta-agonist, a kind of feed additive that can add as much as 30 pounds of saleable meat to an animal in the weeks before slaughter. Beta-agonists, used for many years in the U.S. feedlot industry, became the centre of a controversy in August after Reuters reported concerns within the U.S. meat-processing industry about cattle having difficulty walking.
The feed additive is banned in South Korea and the country's food ministry said it had halted imports from the work site at Swift Beef Co, a unit of JBS USA, and asked the United States to investigate the cause of the contamination.
A JBS spokesman could not immediately be reached for comment.
South Korean authorities were widening tests to all beef imports from the firm's work site, the food ministry's statement said.
"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
"If we further find zilpaterol in U.S. beef or in any other meat, we will take a similar action."
Merck & Co, which makes the leading additive, a zilpaterol-based drug called Zilmax , suspended sales of the drug in the United States and Canada while it carried out an audit of how it was being used, from the feedyard to the packing plant. Merck said it remained confident in the safety of the product, which had sales of $159 million last year in the United States and Canada.
The use of Zilmax is not banned in the United States but has also come increased scrutiny since the largest U.S. meat processor Tyson Foods Inc said in early August it would stop purchases of cattle fed with the feed additive after some animals showed having difficulty walking or moving.
South Korea imported 75,426 tonnes of U.S. beef from January to September, with 4,697 tonnes coming from Swift Beef.
South Korea said it had been strengthening scrutiny of U.S. beef since Taiwan had also detected zilpaterol in U.S. beef.