Cutting equipment designed to fight mad cow disease

The UK-based Silsoe Research Institute has developed a power saw that can more efficiently strip the spines out of cattle and sheep carcasses, claiming to further cut the risk of infecting people with the agent that causes the fatal brain disease vCJD.

Spinal cord from cattle has been banned from food in Britain since 1996, when the link between mad cow disease (BSE) and vCJD was established. If an animal is incubating BSE, its spinal cord could harbour the defective prion protein that causes the disease in both animals and humans.

Abattoirs normally use a bandsaw to split the carcasses of cattle in half. But if the saw cuts through the spine, material from the spinal cord is likely to contaminate other parts of the carcass. The new saw cuts out the spine before the carcass is split.

According to a report from the New Scientist​, technicians at the University of Bristol's research abattoir first split five cattle carcasses in the usual way and then tested each half for two proteins found only in central nervous system tissue: glial fibrillary acidic protein and S-100 beta. This revealed that small amounts of central nervous system material was indeed present on the carcasses after they had been split. Neither the usual abattoir procedure of washing the carcasses with water nor steam cleaning removed the contamination.

For the next step in the research, the team from the Silsoe Research Institute in Bedfordshire used an experimental saw to remove the spines before splitting the carcasses. In place of the long blade of a conventional bandsaw, it has a looped rotating blade designed to scoop out a channel down the back of the carcass, removing the spine while leaving the spinal cord intact. The electrically powered saw can be suspended on a counterbalanced arm to make it easy for operators to manoeuvre. For the moment, it is guided manually, but some automation could be used, the researchers claim.

Tests on carcasses prepared with the new saw showed that it prevented contamination over most of the carcass. The prototype could not negotiate the thick vertebrae at the neck, but, said team leader Andrew Knight, later versions should overcome this problem. "If we touch the cord we've failed,"​ he said. The saw is now being tested in commercial abattoirs.

This is not the first time slaughterhouse technology has been implicated in the spread of prion matter. In 1999, attention focused on how some bolt guns used to stun animals before slaughter blasted particles of brain tissue into their bloodstream.