Brazil has stopped exporting beef to China after it discovered atypical bovine spongiform encephalopathy (BSE) in two domestic meat plants.

In a statement, the director of Brazil’s Department of Inspection of Products of Animal Origin (DIPOA) said that the two plants were in Mato Grosso and Minas Gerais states. Both cases were found through antemortem inspection and the animals were cull cows that were at an advanced age.

Officials said these were the fourth and fifth cases of atypical BSE found in 27 years. Atypical BSE develops is something spontaneously and is not connected with eating contaminated foods. No parts of the affected animals entered the food chain.

According to the DIPOA, The World Organization for Animal Health (OIE) laboratories do not include the atypical cases of mad cow disease when assessing a country’s official risk status.

China is Brazil’s largest beef buyer, typically purchasing more than 50 percent of its beef exports.