I love McDonalds, but I've never worked there and I wonder if I would eat there if I knew what goes on back there.
Why don't you google it and find out
I didn't work for McDonalds, but another fast food chain in high school. They absolutely expected every area to be cleaned and it was strictly enforced, including the restrooms. These chains do have regular inspections, so I think you are safe. A big chain like that is not going to risk a major lawsuit, especially in this day and age of people recording everything with a cell phone.
I assume that as a monolithic franchise, they have certain standards they have to adhere to, whatever you think of the quality and taste of their food. I worked at a chain restaurant for a while, and while it definitely got chaotic, and messy at times, management was always pushing to get things cleaned at every opportunity, and they had high standards for closing cleanup. It wasn't exactly McDonald's, but I imagine for the most part, they are fairly strict there about cleanliness and following food safety guidelines.
No, you really are out in the open with managers working side by side with you. Even customers can see a lot of what is going on. It's probably cleaner there than a few diners I have seen, but that would open another can of worms. You really have nothing to worry about at Mickey D's.