The US Department of Agriculture is requesting more information about how the beef industry plans to remove cattle brains and spinal cords from slaughtered cattle in order to prevent BSE, or mad cow disease, from entering the food chain.

The USDA said it wants "public comment on methods used to prevent cross-contamination of carcasses" with cattle brains and spinal cord, reported Reuters.

Certain parts of cattle aged 30 months or older, including the brain, skull, eyes and spinal cord, have been banned from entering the human food supply because BSE is believed to be carried in the brain and central nervous tissue of infected cattle.

It is believed that humans can contract vCJD, the human form of BSE, from eating infected parts of a BSE-infected animal.

This latest move by the USDA is one of a number of steps it is taking in response to the discovery of a single case of BSE in Washington state in December.

"We want to see if there is any additional scientific information out there," Steve Cohen, spokesman for the USDA's Food Safety and Inspection Service, was quoted by Reuters as saying. "We want to make our methods the strongest they can be."