I'm not aware that there was much of a problem with regular beef.......pork, absolutely....they eat and wallow constantly in their own feces. That's "absolutely" the reason why muslims and jews don't eat pork.....it's a filthy animal to them.
And you're also forgetting there was no refrigeration. Meat had to be eaten within a very short time of being slaughtered. Once the animal is dead the meat begins decay, the warmer the temp the quicker that happens obviously. Now consider the middle east.....pretty warm right? And that's the area where at least in the west, we get most of our history from. So I have no doubt that according to them, if someone got sick from eating meat it had more to do with the animal than decay.
Again, there is absolute irrefutable proof that free ranged animals have an order of magnitude healthier immune systems. The problem is that those animals might not be quite as tasty as animals fed on corn because corn promotes more fat than lean tissue. Than on top of that they feed cows in the U.S a melange of things that make one's stomach turn. They are, not shitting, allowed to mix a certain parts per million of chicken feces into cow feed.....certain parts per million of pasta, candy, concrete......the list goes on about what they're allowed to mix in within "strictly regulated percentages", yeah right
When I eat meat I almost always get the australian free range. It's actually cheaper surprisingly and at least the filets'........are just as good as regular. The other cuts are maybe not quite as good......but that's a tradeoff I"m willing to take.