The USDA now lists 158* as the target for virtually complete lethality for pathogens in beef. (165* is for dark meat poultry.) But what that means is that all pathogens will die instantly at 158*. The same result can be achieved at lower internal temps if a lower temp is held for long enough. As an example, the USDA says that if the center of the meat is at 140* or above for at least 12 minutes, the beef will be pasteurized.
By the way, the special problem with ground beef can be avoided altogether by people grinding their own meat, if they first pasteurize the outside of the piece to be ground by dipping it in boiling water for 12 seconds.
