Apparently there are health concerns related to eating human blood/brains, though, I believe?
From what I vaguely remember reading in the past you just have to make sure it's cooked well.
Not good enough to stop the prions which cause those diseases I listed. According to the Wiki, the process for sterilizing instruments that might have been contaminated with prions involves copious amounts of bleach and lye.
It's because prion diseases are even less alive than viruses are. Where a virus still has a basic wall to hold it together, a prion is basically just a uniquely folded protein that your brain essentially "trips" on, in the process breaking the protein apart into two pieces (each of which then pull parts from their surrounding to become two complete copies of the original). Since it's essentially just a free floating protein in your system without even anything to hold it together, it's even less destroyable than most viruses are, which are basically just a bit of dna surrounded by a protein wall. Less important parts to target and all that jazz.
Err, whaddyamean, less destroyable? Viruses aren't that hard to destroy, per se - the problem is, you can only get so many of the free-floating ones, whereas the real problem demands the engagement of Immune System KGB and if they fail, you suddenly get a LOT of them to deal with.
Prions, meanwhile, aren't tough because they are proteins - most proteins can be and are easy pickings - heat 'em up, digest 'em with proteases, stick 'em in a stew... The problem is prions are not 'most proteins', they are abnormally resistant to the usual tools of the trade, similarly to the issue with amyloids causing Alzheimers and whatnot but with added fun factor of converting your own proteins. Damn things are essentially protein equivalent of zombies, come to think of it.