Although an investigation by the Canadian Food Inspection Agency has failed to discover another case of BSE, following the lone outbreak that has devastated Canada's beef exports, further instances may well follow, a member of the International Committee on Bovine Spongiform Encephalopathy has warned.

Ulrich Kihm, Switzerland's former chief veterinary officer told a press conference in Ottawa that controls over cattle feed were too loose in Canada to guarantee that the country will remain BSE free.

"I'm estimating that there will be other cases in this part of the world," he said.

Meanwhile, bans on Canadian cattle imports to the United States and elsewhere remain in place.