Specified risk material (SRM) is any of various tissues of ruminant animals that cannot be inspected and passed for human food because scientists have determined that BSE-causing prions concentrate there. The term was referred to in the United Kingdom's Specified Risk Material Order 1997 (S.I. 1997/2964), in the United States Department of Agriculture's, and in the Canadian Food Inspection Agency's regulatory response to the first confirmed U.S. BSE case in December 2003.[1] [2] [3]
These can include brains, eyes, spinal cord, and other organs; the exact definition varies by jurisdiction. Under the US regulations (69 FR 1862, January 12, 2004), SRMs are: the brain, skull, eyes, trigeminal ganglia, spinal cord, vertebral column (with some exclusions), dorsal root ganglia (DRG) of cattle 30 months of age and older, the tonsils and distal ileum of the small intestine of all cattle.
The BSE infective agent has been found to concentrate in specific tissues of BSE-infected cattle.
In countries classified as undetermined risk, the OIE code recommends SRM removal as follows: tonsils and intestines in cattle at all ages; brains, eyes, spinal cord, skull and vertebral column from animals over twelve months of age.
In the European Union, SRMs are excluded by law from the human and animal food chain.
The World Organization for Animal Health (OIE) has established recommendations and guidelines for SRM removal based on the level of risk. In the U.S., tonsils are removed from cattle of all ages. SRMs must be removed at slaughter and disposed as inedible material. The dorsal root ganglia must be removed during the deboning process and in animals older than 30 months, the vertebral column (excluding the vertebrae of the tail, the transverse processes of the lumbar and thoracic vertebrae, and the wings of the sacrum) is removed to be certain the dorsal root ganglia is extracted in its entirety.