British inspectors say BSE-contaminated meat may be on sale throughout Britain due to widespread slaughterhouse fraud, The Independent reports. The inspectors accuse slaughterhouses of swapping samples from carcasses to stop them from failing tests to detect the disease.

The article says current rules call for brain stems of all cattle more than 30 months old to be checked, but some abattoir owners are suspected of substituting the brains of younger animals to ensure the meat is sold.

Inspectors belonging to the public service union Unison reported the alleged practice at two British slaughterhouses. A third case is under investigation in Northern Ireland, where a lab said DNA testing discovered samples taken from two cows could not be from animals more than 30 months old.