SEOUL, June 5 (Reuters) - South Korea has temporarily suspended quarantine inspections of imported U.S. beef after some meat for U.S. domestic consumption was wrongly shipped to the Asian country, an agriculture official said on Tuesday.

The move effectively prevents U.S. beef from reaching South Korean consumers and is the latest in a series of interruptions to supply since U.S. beef imports resumed in April when South Korea lifted a 3-year-old ban on the meat imposed due to a U.S. outbreak of mad cow disease in 2003.

Seoul asked Washington to trace if any other beef for U.S. domestic consumption had been exported to South Korea since mid-April.

"The suspension is temporary. We will stop issuing quarantine certificates to U.S. beef importers until the U.S. sends the results of investigation to us," said the official who asked not to be named.

South Korea, once the third-largest importer of U.S. beef, said on Monday it banned beef from two plants owned by Cargill Inc. [CARG.UL] and two owned by Tyson Foods Inc <TSN.N>

Cargill sent 15.2 tonnes of beef containing two boxes filled with short bones, while Tyson shipped 51.2 tonnes of meat that should have been sold in the United States only.

Seoul has sent back all 66.4 tonnes of beef to the United States.

At present, Seoul allows imports of boneless U.S. beef from cattle less than 30 months old, while the U.S. has no restriction on age and meat cuts for domestic consumption.

Cargill and Tyson said overnight they produced beef for domestic consumption and it apparently was exported by customers, not by themselves.

Some 227 tonnes of U.S. beef have been released onto the South Korean market since April when the country accepted the first shipment of boneless meat since December 2003, according to the ministry.

The country has been expected to be ready by September to resume imports of U.S. beef with bones, while Washington has called on Seoul to ease import restrictions to ease the passage of a bilateral trade deal.

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