If, for instance, your burrito worker did something egregious, they could be held criminally liable, and depending on the specific situation, the employer could also be held civilly liable.
I say "depending on the situation" because it is the duty of the vendor to ensure best practices are followed: sanitary restrooms, soap and running, clean water for cleaning up, etc. And a nontrivial number of places do so because they know an inspector is coming at some point and they will suffer if they do not comply.
But it is harder to hold the vendor liable if all reasonable precautions and amenities are availed by the vendor, and all proper education, but the end of line worker decides to ignore all of it one day.