// How did the first person get this, then, if it didn't come from bats, but lack of hygiene? //
It has nothing to do with lack of hygiene or eating disgusting (to us) food.
The virus passes on through coughs and sneezes. It is in the tiny droplets in our breath. We know it originated in bats, so a human or a intermediary animal breathed the same air as a bat, and it crossed species. It has now crossed to big cats, again through airborne infection from humans.
It could well cross into cows and pigs, but that will not contaminate our food. We get it from live animals, not dead and cooked ones.