Mad cow disease has scared Europeans into a frenzy about all their food, not just beef. Now some activists are hinting that the disease may be here in the U.S., despite there being no evidence. The strategy is designed to put commercial interest in the position of trying to prove a negative. Witness this exchange between CBS’ Bryant Gumbel and Dr. Emily Senay on December 12th’s Early Show:

GUMBEL: So what are you telling me? Not a problem here? Not going to be a problem here.
SENAY: It depends on who you ask. Many experts believe that we have managed to prevent it from coming here. However, there are others who are most concerned and believe that, no, it’s just a matter of time before it turns up here. It really depends on who you ask.
GUMBEL: If you’re traveling abroad, you going to eat a burger?
SENAY: You know, I–it’s probably just a psychological…
GUMBEL: It’s just a simple yes or no. I mean…
SENAY: I don’t think so. I think if I–I would probably avoid beef. And the CDC says that if you’re concerned, that’s what you should do.