How was his post incorrect? He didn't even mention what it was caused by and you jumped all over him. Your post is INCORRECT though; the misfolded prions are in spinal tissue AND the brain. Infection is spread when other cattle are fed meat and bone meal comprised of infected animals. The spinal tissue alone, as you assert, doesn't have to "somehow" get into the food chain. Offal may not be on your menu but it is very common, and calf brain is a common dish abroad, hence human infections. Plus with a unusually high resistance to heat and an incubation period of multiple years it is not something that has just disappeared.
Than you can get into Variant Creutzfeldt-Jakob disease which is passed on genetically and may take 30-50 years to really appear. There are a lot more cases that will come to light.