Worried About Mad Cow?

Despite the rapid pace of their investigation, Canadian officials say they can't yet rule out the possibility so-called mad cows have entered the food system.

At a press briefing in Ottawa on Friday, Canadian Food Inspection Agency senior veterinarian Gary Little said good records of the infected cow's history are helping speed the process.

Even though that means potentially infected cattle could have made their way into the animal and human food supply chains, CFIA officials sought to assure consumers there's no cause for concern.

"Those animals would represent a very low risk potential for an animal carrying the infection into the food supply," Health Canada's Paul Mayers said.

"What we can't say is that would be a zero-risk event, because zero risk doesn't exist."