Now, litter containing waste from chickens legally can be processed and fed to cattle under some circumstances, Sundlof said. Some have questioned whether chickens that ate material prohibited for cattle could recycle the banned byproducts back to cows that ate their litter. The abnormal proteins believed to cause mad cow disease have proven resilient, and it is unknown whether a chicken's digestive tract could kill them. Sundlof said in an interview. In remarks to a public meeting regarding mad cow, also known as bovine spongiform encephalopathy, Sundlof said regulators were re-evaluating other practices now exempt from cattle feed bans.
Plate waste is food served to people in restaurants that later is discarded.
Some companies reprocess the leftovers into animal feed. The steak might carry spinal cord tissue, which along with brain parts is considered highly infectious. Some 100 people in Europe have died from or been diagnosed with the human version of mad cow, known as variant Creutzfeldt-Jakob Disease .