South Korea joined China, Japan, South Africa, Egypt and Saudi Arabia in halting Brazilian imports in connection with an atypical case of bovine spongiform encephalopathy (BSE) that was detected in an animal that died in 2010 in the southern state of Parana, the agriculture ministry said.
The six countries take in only 3.8 percent of Brazilian beef exports, according to the economic daily Valor.
Brazilian officials insist the Parana case poses no risk whatsoever to public health or to animal hygiene.
Several countries including the United States, Canada, Japan, Portugal and Britain also have recorded atypical cases of BSE, they noted.
With nearly 200 million head of cattle, Brazil is a leading beef exporter with some 180 countries as customers this year.
Between January and October, it exported one million tons of beef, mainly to Russia, the agriculture ministry said. Other major customers are China and Hong Kong.
Brazil is a member of the BRICS bloc of emerging powers, which also includes China, India, Russia and South Africa.
More than 190,000 cases of mad cow disease have been detected in the European Union since it was first diagnosed in Britain in 1986, forcing the destruction of millions of cows.
More than 200 people around the world are believed to have died, most of them in Britain, from the human variant of the disease, which was first described in 1996.
Scientists believe the disease was caused by using infected parts of cattle to make feed for other cattle.
Authorities believe eating meat from infected animals can trigger the human variant of the fatal brain-wasting disease.