The risk level for ground meat can be managed. The worst risk comes...
...from meat ground in huge grinding machines in meat processing plants that mix cuts of meat from many different animals in one batch. Stores that don't grind their own hamburger and have it shipped in from another site pre-ground fall into that catagory. Also, the 3#, 5# and 10# "chubs" are something I never buy. Too dangerous, if you like your burgers on the rare side. Picture 100 steers in one 5# roll.
Ground beef made "in-store" is much safer. That is, if you trust your meat counter guys where you shop.
If I am absolutely craving a great burger, I go grab a boneless chuck roast with about 20% fat and have the butcher grind it for me. The chances of getting any nasty bugs go way down, assuming, again, that I can trust the butcher to take good care of his grinding equipment.
Michael