A friend of mine services kitchen equipment for a living (in the UK), he regularly tells me McDonald's are the cleanest establishments he visits.

imo mcdonald's coca-cola taste is the best because they're the only ones that clean their fountainheads regularly.

I can vouch for that. Our McDonalds cleaned them every night-thoroughly. Our restaurant was also really quite clean. Even the 'icky' bits got a thorough cleaning at least once a week-our maintenance guy would break down the fryers and grill area and polish them to a shine.

Be glad you don't know what a horrible task that is -- "cleaning the vats". Especially the one used for Filet-o-Fish all week.

And the cleaning agent remains in the oil for subsequent frying. (Or that was the practice 30 years ago, anyway.)

It's easy to keep clean nowadays now that, for most hours of the day, nothing but fries are actually cooked in real time -- just reheated and assembled.

It's not like the old days, where you could get any sandwich fresh as a custom order, and otherwise a maximum of 10 minutes post-wrap hold time.

Oddly, several Jack-in-the-Boxes here are the most clean, with Carl's Jr. being worst -- a complete inversion from 20 years ago.