On Tuesday, December 23, the first reported case of bovine spongiform encephalopathy (BSE), or Mad Cow disease, was announced by the US government. The case was later confirmed by British laboratories specializing in BSE.

The single Holstein dairy cow from Washington state was slaughtered on December 9 and its beef has been traced to 8 US states and Guam.

The announcement was made amidst a flurry of government attempts to quell fears. Kenneth Petersen, a spokesman for the US Department of Agriculture Food Safety Inspection Service, said on Sunday, “The meat per se, because it did not contain any spinal cord material, we think is a very low risk to consumers.”

As a protective measure, about 10,000 pounds of beef originating from Vern’s Moses Lake Meat Co. in Moses Lake, Washington where the cow was slaughtered has been recalled by the department.

Still, all eyes have been on the quick-serve industry. McDonald’s, Wendy’s, CKE, and other large quick-serves issued press releases saying none of their beef came from supplies involving the BSE case. Even with a short trading day on the 24th, McDonald’s stock fell more than 5 percent.

Reassurances will only matter if this case can be isolated. Outbreaks in Europe and Japan over the last decade have had serious negative effects on beef consumption and, in turn, the quick-serve industry.