However, children who have never eaten beef might be safer if they are never fed it, Dr Stephen Dealler told MPs.
"I stopped eating beef in 1988, but my statistics suggest that for people who have kept on eating it, there is no advantage now in stopping," Dr Dealler said.
"The added risk of continuing is very small." He added that giving up beef might halve the risk.
However, he added: "I can't show statistically that it's safe for children." Dr Dealler and Dr Harash Narang, who claims to have developed a urine test for BSE and CJD in live cattle and humans, were giving evidence as independent scientists to a joint Commons Select Committee on agriculture and health.
Dr Dealler's also challenged many of the Government's assumptions about the public health risk from "mad cow disease", or BSE, and accused it of understating the number of cases.
He warned too that if BSE can be passed to humans - a possibility recently admitted by the government - then "in the worst case" there might be millions of cases of CJD in Britain sometime in the next century, after incubation periods of up to 50 years.