There's a very simple solution to the salmonella and E. Coli O157:H7 issue. Stop feeding cattle grain and other non-grass crap. Since cows are supposed to eat grass, they're significantly less susceptible to salmonella and E. Coli if they eat what their stomachs are designed to digest.
Problem solved.
In theory.
But instead of, you know, just feeding cows grass instead of corn!, corporate agribusiness is introducing a vaccine for E. Coli O157:H7. Yeah, I'm sure this will solve the problem and won't create any unwanted side effects or resistant strains. Yummy.