JB, commenting on an earlier post, asked about an article alleging that cattle feed in the U.S. still contains mammalian tissue including cattle parts. As most people presumably know, the disease known as Bovine Spongiform Encephalopathy in cattle, variant Creutzfeldt-Jakob Disease in humans, and popularly called Mad Cow Disease, is transmitted exclusively by eating contaminated tissue. That means that cattle, who are by nature herbivores, get it by canibalism. It was for many years the practice to grind up waste from slaughterhouses, including spinal cord and brain tissue, and add it to cattle feed.
The infectious agent in BSE/vCJD/Mad Cow Disease is called a prion. For a long time, most biologists didn't believe these things even existed, and thought their discoverer, Stanley Prusiner, was a crank. They were wrong! Proteins are long chains of components called amino acids that fold into complex shapes in solution. Prions are abnormally folded proteins, which can catalyze the abnormal folding of similar proteins. Once they get established in a cow's brain, or yours, they spread, causing holes in your brain until you are first insane, and then dead. Prions are not destroyed by cooking.
So, ever vigilant, the FDA banned mammalian nerve tissue from cattle feed in 1997. Whoops. It seems they left a few loopholes, specifically:
- They allowed mammalian blood and blood products to be fed to cattle. Apparently they didn't think blood could contain prions. Wrong.
- They allowed "poultry litter" to be fed to cattle. That's the chickenshit, feathers, spilled feed and what not that gets shoveled off the floor of the henhouse. I kid you not. The problem is, they allowed cattle parts to be included in the chicken feed and -- you get the idea.
- They allowed restaurant table scraps to be added to cattle feed.
- They did not require facilities that process cattle feed (cattle parts not allowed) and other animal feed (cattle parts allowed) to use separate production lines, i.e. cross contamination remains possible.
Well, you've got questions, we've got answers.