Clever wording. "Study finds Fast food ice can be dirtier than some toilets".
And what's more, "dirtier" is a HUGE "waffle-word" as it is used here. Clearly, it is intended that we interpret "dirtier" in the qualitative (and entirely subjective) sense of "nastier." Apparently, though, it is only justified (if at all) in the quantitative sense of "parts-per-million" or "parts-per-billion" or some such. Not all bacteria are created equal, though - and the ones you're apt to find in a toilet are not necessarily the same ones you're likely to find in an ice-maker.
And even our concerns over "toilet" bacteria are driven FAR more by primal scatalogical fears than by reasoned thought & rationality. After all, all the "nasty stuff" that goes into toilets came out of our bodies in the first place
[1]. Serious problems arise when that "nasty stuff" is allowed to sit, stagnate and serve as a "breeding ground" - but that's not the case with modern toiletry/plumbing.
We are being invited to apply our (survival-advantaged) disgust with shitty things to fast-food ice-makers. And that's a pretty shitty thing to do ...
The manic "germophobia" exploited by this "study" is probably a greater & more active danger than the germs & bacteria themselves - especially when it manifests in such ways as the widespread use of "anti-bacterial" soaps. (A thing for which we are one day going to pay ...)
[1] Usually because it's stuff the body doesn't need, can't use or is present in quantities too great for the body to process. Despite our shiversome disgust, it is generally harmless, in and of itself. There are, of course, exceptions to this - as in the case of "infected" effluvia from someone who is already diseased, poisoned, etc. These exceptions are why our "overreaction" to "shitty things" is a survival advantage.