Six countries have banned imports of Brazilian beef, including No 6 importer Chile, since a case of atypical mad cow disease was confirmed last month, Brazil's foreign trade secretary Tatiana Prazeres said on Wednesday.

Brazil, the world's No 1 beef exporter, is considering retaliation at the World Trade Organisation (WTO) if the countries do not lift the bans, Prazeres told reporters in Brasilia, insisting that Brazilian beef is safe to eat.

"There is no basis for these decisions on health parameters and the government is analysing what measures will be taken," she said. "Taking action at the WTO is on our radar."

China, Japan, South Africa, Saudi Arabia, Chile and Jordan have informed Brazil about their export bans since the World Animal Health Organization (OIE) said a cow that died in 2010 had atypical bovine spongiform encephalopathy (BSE), she said.

Chile imported 62,600 tonnes of beef from Brazil between January and November 2012, according to the agriculture ministry. It imports the most beef among the countries that have banned Brazilian beef.

Prazeres estimated that 4.4 per cent of the country's total beef exports have been affected by the bans. Even with the measures, however, beef exports rose to 83,700 tonnes in December compared with 82,700 in November and 63,100 a year earlier according to trade ministry data released on Wednesday.

The 13-year-old grass-fed cow, which had been kept for breeding in the state of Parana, never developed BSE, commonly known as mad cow disease, but it tested positive for the protein that causes the disease.

The Paris-based OIE, which confirmed the atypical BSE diagnosis, has maintained Brazil's status as a beef producer with negligible risk of mad cow disease.

Officials from the Secretary for Animal and Plant Health at Brazil's farm ministry said on December 21 that Brazil would give the countries that curbed its beef imports until March before pursuing legal action at the WTO.

Brazil launched a diplomatic offensive to distinguish "atypical BSE," which is caused by a random genetic mutation more common in elderly cattle, from BSE cases in the 1980s and 1990s in Britain and elsewhere in Europe that were caused by contaminated animal feed. – Reuters