High Pressure-Temperature Inactivation of TSE Agents in Specified Risk Materials (SRMs)

Findings: Government precautions against the spread of Bovine Spongiform Encephalopathy (BSE, or �mad cow disease�) include a ban on the use of highly contaminated tissues (so-called Specified Risk Materials, or SRMs) from slaughtered cattle, which must therefore be destroyed. Heating contaminated meat products under ultra-high pressure had been shown in earlier studies to reduce infectivity by up to a hundred thousand-fold. We have now used the same process on rendered SRMs and shown that a maximum infectivity reduction of one hundred to one thousand-fold. It is possible that the dehydrated powder form of rendered SRM inhibited pressure-temperature inactivation, and that crude (unrendered) SRM would be more susceptible to the process. However, even if infectivity could be totally eliminated in unrendered SRM, the huge tonnage of such material would make the ultra-high pressure process impractical as a means to �recover� SRM for commercial use.