Inactivation of the BSE agent.

In the studies carried out so far, the BSE agent has proved to be just as resistant as other TSE agents to inactivation by procedures such as autoclaving or exposure to sodium hydroxide that are effective with conventional microorganisms. However, in common with other TSE agents, the BSE agent appears to be effectively inactivated by exposure to sodium hypochlorite solutions containing high levels of available chlorine. Not surprisingly, the BSE agent has been found to survive at least some of the rendering processes that were used to process tissues discarded by abattoirs in the EU during the early 1980s. Despite the survival of BSE infectivity after autoclaving or exposure to sodium hydroxide, it is known that combining these procedures results in a very reliable degree of inactivation for TSE agents generally. The combination of heat and alkali has also been shown to be effective with a mouse-passaged strain of BSE agent, even at a temperature of only 100 degrees C for a minute. Also, in carrying out BSE-spiked validation studies relating to the safety of bone-derived gelatin, it has also been found that the exposure of acid-treated bone (which is free from any obvious remains of fatty or proteinaceous tissue) to 0.3 M sodium hydroxide for two hours knocks out any residual BSE infectivity.