For example, milk is pasteurized because dairies are too lazy careless to keep literal shit out of the milk. Sure, they filter out the chunks, but a huge number of pathogens remain.

When heated those cells die, but guess what? All of their cellular machinery is still present in the final product. It can’t infect you as such, but it sure as hell isn’t anything that you should be drinking.

Look up the USDA standards for contamination. Food production involves industrial processes with necessarily loose safety margins, due to the relative scale of operations. If a small farmer caused this outbreak, they would be burnt to the ground, but anyone think this will impact the guilty beyond a minor dip in stock price?

Those corps do not care one whit about individuals any more than Apple or Facebook cares about their customers, unless you count how it affects their next quarterly statements.

So, the lettuce was last washed before being shredded. Then it was shredded in machines or by hand or something. It may have been misted, I guess, like you see in some grocery stores, but the point is that there was ample opportunity for contamination by equipment, vessels, or utensils, in the processing facility, during or after washing the whole lettuce.