The UDSA lowered the recommended temperature from 160 ºF to 145 ºF citing increased production methods as a reason for creating safer meats for consumption. The reason for the original recommendation was to kill off the natural bacteria in the meat to a safe level.
It’ll be an interesting change for those of us that learned the cooking temperatures for cooking meat. It will be an even harder change for those of you that relay on thermometers such as this for cooking. They’re now obsolete and will more than likely replaced by newer models in the coming weeks in time for the summer season.