why would they? if you wanted someone trained in food chemistry then your coffee would cost 2x. hell, chances are the manager doesn't know much more, either.

they have dishwasher, they put cups in dishwasher, they run, they serve in clean cups.

it's clear from the article that this is an issue across the entire food service industry, and has nothing to do with whether or not your pimply faced barista knows what the safe level of rinse aid in pre-made clears is.

They know better than to drink out of the machines which were supposedly cleaned when they weren't there to know for sure.

In the best-run high-turnover locations where cleaning agents are used according to a rigorous schedule proven to prevent slime and bacteria, it might be even more likely to have exposure if the chemicals are habitually incompletely rinsed from the apparatus afterward.