The entire meat supply is widely contaminated with mad cow disease. Avoiding meat is the only reliable way to protect yourself.
Mad cow disease is a progressive brain-wasting disease that is always fatal. It is caused by a type of defective protein known as a prion and cannot be cured. The factory farming practices of feeding animals on the nervous tissue of other animals first caused the ballooning spread of mad cow disease and created the current crisis. When it became clear what had happened, many countries banned feeding the tissue of ruminants (cows, sheep and goats) to other ruminants.
There’s just one problem: ruminant tissue (including nervous tissue) is still fed to everything else. That means that chicken, farmed fish, and any other kind of meat might contain mad cow prions. To make matters worse, fish meal, chicken feces and the bodies of other animals can then be fed straight back to ruminants intended for human consumption. An extra step has been added, but the concentration of prions in animal flesh continues. Cooking does not destroy prions; even radiation leaves them untouched. Ultimately, the only way to reliably reduce your risk of mad cow disease is to avoid farmed meat products altogether.