The New York Times has a really scary story on the dangers of getting E. Coli from hamburger.
It's a long story, but the short summary is that every time you eat hamburger you are risking your health and your life. There is little or no possibility that the meat packers can or will guarantee their product is free from contamination. The FDA will not permit the information to be released because the meat packing companies treat the systems of hamburger safety as trade secrets, and by law the FDA must protect trade secrets. So the problem starts with the meat packers and runs directly back to Congress.