ABSTRACT
Nearly two and a half decades after the emergence of a new transmissible spongiform encephalopathy (TSE) in bovines of the United Kingdom, the ban on so-called specied risk material (SRM) remains the most important measure to effectively reduce any potential oral human TSE exposition risk from the food chain. Already, in 1988, milk from clinically TSE-affected dairy cows was prohibited in the United Kingdom as a measure of preventive consumer protection in absence of any scientic prove [67]. In the end of 1989, the so-called specied bovine offal was legally dened and banned [68]. Due to sparse knowledge on this new disease, data from scrapie of sheep were used for estimating the potential risk and dening respective risk tissues. Consequently, this denition was imperfect and subject to change on the basis of new scientic data on TSE. Tissue diversity of TSE infectivity in bovines proved to be more restricted than in scrapie, especially excluding lymphoreticular tissues such as spleen or lymph nodes. Unfortunately, this early legal denition proved to be rather ineffective in practical circumstances, in particular the removal of the brain from the skull, which was still introduced into the food chain via production and use of mechanically recovered meat. As a consequence, the denition was broadened to such material that could probably be contaminated by risk tissues. Today, the SRM (18, last amended on 20/04/2009) is legally dened in bovine animals as (1) the skull excluding the mandible and including the brain and eyes and the spinal cord of animals aged over 12 months; (2) the vertebral column excluding the vertebrae of the tail, the spinous, and transverse processes of the cervical, thoracic, and lumbar vertebrae and the median sacral crest and wings of the sacrum, but including the dorsal root ganglia, of animals aged over 30 months; and (3) the tonsils, the intestines from the duodenum to the rectum, and the mesentery of animals of all ages. In addition, when harvesting the tongue of bovine animals (of all ages) for human consumption, only its part rostral to the lingual process of the basihyoid bone is to be used.
