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South Korea has banned the import of certain shipments of U.S. beef, following the discovery of the feed additive known as zilpaterol in meat supplied by the U.S. unit of meat processing company JBS, Reuters reported.

The use of beta-agonist feed additives such as zilpaterol is prohibited in most European and Asian markets. The substances are used to promote muscle growth in animals but they are also believed to have a negative effect on their overall health. A video that became public in August showed animals that had been fed zilpaterol showing signs of distress, such as struggling to walk. As a result, one of the leading U.S. meat processing companies, Cargill, stopped the use of beta-agonist additives.

South Korea's food ministry announced Tuesday that it was suspending imports of U.S. beef supplied by a Swift Beef Co plant operated by JBS USA and called for U.S. regulators to look into the case. It added that the contaminant was discovered in a batch of 22 tons of beef, Reuters reported.

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The ministry explained that it had put U.S. beef imports under tighter scrutiny following Taiwan's announcement that it had found zilpaterol in products imported from the United States in September. Taiwan's authorities requested that the imported meat be destroyed or sent back. South Korea intends to take similar action, a spokesman for the country's food ministry told Reuters.

Between January and September 2013 South Korea imported 75,426 tons of U.S. beef, with 4,697 tons of this shipped by Swift Beef Co.