Meat from the animals was prevented from entering the nation’s food supply, USDA said.

Agriculture and health officials have scaled up testing of meat and dairy products and livestock, as an outbreak of bird flu has expanded in dairy cattle.

Two US dairy workers have tested positive for bird flu since the virus was first detected in cattle in late March.

To date, testing on beef tissue has been completed on 96 of 109 muscle samples that were collected as part of a meat safety study, USDA said on Friday. It plans to report further updates as testing is completed.

The agency’s personnel identified signs of illness in the positive animal during the post-mortem inspection and prevented the meat from entering the food supply, according to USDA.

“These actions provide further confidence that the food safety system we have in place is working,” the agency said in a statement.

The department had confirmed bird flu infections in 58 dairy herds across nine states.