Senior Press Secretary Choe Geum-nak said stronger quarantine inspections would be enforced instead, with inspections increased from 3 percent of U.S. beef shipments to 50 percent.
"Judging from the information we have collected so far [we] believe stricter quarantine inspections are sufficient," he said.
Yonhap News Agency reported U.S. beef shipments cannot receive customs clearance unless they pass quarantine inspections. South Korea only imports beef from cattle younger than 30 months with all "specified risk materials removed," meaning parts of the animal capable of transmitting mad cow, or Creutzfeldt-Jakob disease, to humans.
The disease is so far responsible for about 200 deaths of humans worldwide, mostly in Britain. In the United States, where there have only been four cases in cattle since 2003. South Korean government officials say the case discovered in California would not directly affect South Korea's supply, because the cow in question did not fall under import regulations.