I am always asking questions related to food safety for some reason. It's the natural sciences student in me that never graduated apparently...
Reading up I'm finding I'm to put the grinder attachment in the freezer first, to flash freeze the meat and then I'm only to grind only a couple of pounds to keep the apparatus and meat from heating up too much and putting the meat in "the danger zone" for too long.
I am targeting a medium burger so NOT having microbes in play would be highly desirable .. but if my meat is "infected" it seems to me it's going to be infected at the end of a 140deg cooking process period regardless of temp while being ground. Is the thinking that my small amount of microbes if ground while cold is safer than the multitude that would grow if I leave the beef out for a long period and room temp?
100 microbes won't make you sick but 10,000 microbes will? I do remember, from science classes, how fast microbial critters multiply.