Britain's Food Standards Agency has admitted for the first time it might have to tighten the controls governing the sale of lamb because of the risk of BSE infecting sheep.
The agency has, until now, said that existing controls are adequate given that BSE in sheep is only a theoretical possibility, but the collapse of an important experiment to test sheep for the cattle disease has prompted a change in policy. The experiment, which involved testing sheep brains collected in the early 1990s, was thrown into disarray when scientists discovered they were apparently testing a collection of cattle brains by mistake.
Sir John Krebs, the agency's chairman, announced he has ordered a wholesale review of the current research into BSE in sheep, with one outcome being a new set of safety measures to protect public health. Existing measures, which include a ban on certain offal products such as sheep brain and spinal cord, might have to be extended if the precautions were judged to be inadequate, Sir John said.
"We could take other parts of the offal out of the body before it goes into the food chain or we could, for example, consider an age cut-off for lamb going into the food chain. Those are the kind of precautionary measures that might be considered in the future," he told the BBC.
One senior government adviser has already criticised the existing precautions as "illogical, inconsistent and inadequate", arguing that if BSE has infected sheep it could pose a far greater risk to consumers than BSE in cattle. Richard Kimberlin, a former member of the Spongiform Encephalopathy Advisory Committee (Seac), said in The Independent in August that the agency's policy of waiting until the evidence emerged of BSE in sheep could be a grave mistake.
"Why play this waiting game? Would it not be wise to assume that BSE is present in sheep and to improve the control measures? This would put us in a much better position if and when convincing evidence of a risk emerged," Dr Kimberlin said.
Sir John's review of the research into the risks of BSE in sheep includes measures designed to assess the possible exposure of the British population who have eaten lamb over the past decade and to identify the main routes of exposures.
The agency has asked Professor Roy Anderson of Imperial College in London to quantify how much BSE there might be currently within the national sheep flock if the disease spreads from animal to animal much like scrapie, a similar brain disease in sheep. Professor Anderson's team will also assess the relative infection of sheep with BSE compared with infected cattle.
Dr Kimberlin, who was instrumental in introducing the bovine offal ban in the winter of 1989-90, suggested tightening the ban on sheep offal – to include, for instance, lymph glands – without waiting for the results of continuing experiments. "We now know that several tissues from BSE-infected sheep, including lymph nodes, pose a greater risk than the same tissues from infected cattle," he said.Reuse content