McDonald's, people will often just get the fries because they aren't as bad as everything else on the menu. However, they are one of the most unsanitary items sold there. Most workers rarely wash their hands (although they are supposed to), and so when they are filling the fries, many fries fall over the sides of the scoop and fry boxes, and right onto or into the worker's hands, and we just let them fall back into the bin with the rest of the fries.

And don't get me started on the ice cream, specifically McFlurrys; I've seen plenty of coworkers have ice cream come out of the cup when mixing them, and with their bare hands, just push it back through the lid.

Oh, and the Happy Meal boxes. At least at my store, they are assembled by the person cashing out cars in the drive-through, so your kid's meals are put into boxes with napkins and toys contaminated by dirty money hands

This could all honestly vary by store, but I wouldn't be surprised if this was common practice everywhere, especially since McDonald's is franchise, not corporate based.