h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I used to think more like you... that all these food scares would never amount to much, and that healthy eating was overrated. Recently, I have been trying to find out more about BSE and other TSEs (transmissable spongiform encephalopathies), and I have stumbled upon a lot of alarming material on the internet. One nasty article about meat production *in general* in the USA is well worth reading: http://chetday.com/cannibal.htm
I'm sure much of it applies to other 'developed' countries.
With regard to BSE and the safety of eating beef as a human, I think the damage is probably done already. No-one is 100% certain about what the agent of the disease is, but if it is prion proteins, then your chances of contracting CJD could be related to *how much* affected beef (and other meat) you've eaten.
TSEs have been shown to have quite variable incubation periods, so who knows whether we are yet to suffer a CJD epidemic? If we do, however, it isn't likely to just be a UK based thing.

Other countries have BSE as well. They just don't call it the same thing...
There's also the problem that BSE almost certainly did not come from scrapie, so that idea is scuppered. It may be that any ingestion of the brain of your own species puts you at risk from a TSE, e.g. Kuru, caused by eating human brains.
If prion proteins do cause BSE, they would have to be pretty remarkable things to survive a) the cooking process and b) your digestive system. I'm not saying that the theory is wrong, but there is no direct proof.

Prions are incredibly tough wee cookies. I mean frightengly so. As a protien goes they are incredibly difficult to denaturate permenantly, so once back in a receptive host they revert to their active shape, and wait until they meet a precursor protien. Intense heat doesn't seem to destroy them, with some reports saying they survive total incineration of their host. The digestive sytem is an efficient destroyer of all things organic - but still a small amount of material can get into the bloodstream intact. Just think of all the parasites that live on cow's blood - could they transmit prions? at the moment no one knows...
BCNU - Crescent

Having not read much about prions, I can't really comment, but it still seems extremely unlikely to me that any protein tertiary structure could survive temperatures above 100 degrees C. As to parasites on cow's blood, again, I don't really know anything. But given that prion is a membrane protein in its natural form, how could they transmit it? It does not strike me as something they could just aquire!