FDA wants to limit the use of some cattle materials in medical products in order to keep them free of the BSE-causative agent. The proposed rule would cover drugs (prescription, over-the-counter, and homeopathic), biologics (such as vaccines) and medical devices intended for use in humans, as well as drugs intended for use in ruminant animals. The materials include:

• Brain, skull, eyes and spinal cords from cattle 30 months and older.
  
• Tonsils and a portion of the small intestines from all cattle regardless of their age or health.
  
• Any material from "downer" cattle.
  
• Any material from cattle not inspected and passed for human consumption.
  
• Fetal calf serum if appropriate procedures haven't been followed to prevent its contamination with materials prohibited by this proposed rule.
  
• Tallow with more than 0.15% insoluble impurities if the tallow is derived from materials prohibited by this proposed rule.
  
• Mechanically separated beef.

To ensure compliance, FDA proposes to require firms keep records to demonstrate any cattle material used as an ingredient in these medical products or as part of their manufacturing process meet the rule's requirements.
-- FDA release