Sometimes, the things that are expected to be dirty are often cleaner than those that are expected to be clean.
For example, in the mentioned toilet and shopping cart, the toilet will be cleaned far more often than the cart will be, just because the toilet is expected to get dirty faster and more frequently than shopping carts, hence deserving a regular hygiene and maintenance regimen.
I'd not be surprised of someone finds restaurant ketchup dispensers to be dirtier on the outside than toilet door handles.
That'd be right...in NZ, we had a microbiologist swab dozens of surfaces including toilet environs for germs and the two worst were computer keyboards (from eating and/or going to toilet without cleaning their hands properly) and escalator rails.
True. I took swabs from the women's bathroom in grad school. The culture from the sink was worse than the toilet.