Well that’s pretty rude. The dangers of e-coli or other contaminant or miniscule if the beef is properly sourced and processed. The most common contaminants are found on the surface of the beef. That’s a big issue if you’re running hundreds of pounds of beef through a processor at a time, and shipping it out - that ground beef has a TON of surface area. It’s not an issue if you start with a beef round with very little surface area, and have a butcher process it for you in a grinder that’s clean.
Either way, my 95 year old grandmother WAS pretty cool, and she was tough as hell. She weighed no more than 120 lbs, and bowled with a 16 lb ball.
I’ve lived in small-town Wisconsin for 40 years and I’m quite familiar with the tradition. They used to (maybe still do) have them at the Christmas parties at the bars. I never had one but not because raw meat grosses me out.
l salt and eat raw whatever beef I’m about to cook all the time.
I grind my own hamburger on occasion. In small batches raw hamburger can be very safe*. I boil the cuts of beef for about 15 seconds before grinding. It leaves a small bit of overcooked beef on the outside but it’s undetectable after grinding. I assume butchers do something similar.
* - I was going to say “perfectly safe” but few things are that safe.
Your question made me curious so I googled “beef ceviche” and found this: I present someone’s “ground beef ceviche” recipe. No thank you… I don’t think so! That bad photo of the end result is not helping the appeal at all: https://cookpad.com/us/recipes/360823-ground-beef-ceviche
(Don’t click the link if you get nausea easily)
There’s a dish in northern Italian cuisine called carne cruda or carne cruda all’albese, which is similar to steak tartare but seems to use lemon juice to denature the beef proteins somewhat.
One could, in theory, pasteurize beef just barely in the “kill zone”. That takes longer the lower you go, IIRC USDA FSIS pegs the 7-log10 lethality at 130 °F at about two hours. (With some caveats, so please nobody use my post as a guide.)
What I’m not sure of is if you can go low enough to avoid an appreciable change in texture without dropping into the growth zone. I’ve cooked beef lower than that but never tried grinding it after.