Here's the link: http://www.littlebigcat.com/blog/mad-cow-discovered-in-california/
If you want to protect yourself and your pets from BSE, you must avoid all beef and mutton products (mutton may contain similar prions that, in sheep, cause a disease called “scrapie.”). In pet food terms, you would want to avoid all forms of beef, including “meat by-products,” “meat and bone meal,” “beef and bone meal,” “animal digest,” “animal fat,” and any mammal product not specifically designated as something else (“lamb,” for instance). Even that may not be enough, since even “lamb” may contain beef parts; since the name “lamb” can be applied as long as lamb is the predominant ingredient (i.e., at least 51% of the product). The term “meat” is restricted to cattle, sheep, goats, and swine, so any product simply designated as “meat” will usually contain beef.