Once upon a time my fridge was bursting in seams, and I was uncomfortable leaving the 3 thrumbo corpses outside, because I might forget about them. So I put them in my hospital, which is refrigerated when not used and cooled when I have some sick (a really warm rainforest map, with around 25*C in winter). Nobody cared. Room dirtyness didn't increase.
* corpses should have inherent dirtyness, like workshops do
* meat chunks should have inherent dirtyness
* maybe pot plants should have a bit of dirtyness. They require soil. They allow microorganisms to live on them. There are other options to make hospitals nice-looking, mostly sculptures.