seeformiles
Lost in the wood
Cajuns have been cooking authentic (and delicious) "dirty rice" for many decades before hipsters began to soil their fries.
I think the more recent usage is almost a backlash against healthy eating drives by the govt, Jamie Oliver, the purveyors of organic food, etc. Anything I’ve seen that’s referred to as “dirty” appears to translate to any foodstuff overlaid with excessive sugar, salt and fat (which is always going to taste great ). Perhaps better terms might be “Guilty”, “Immoral”, “Shameful”, etc. - in fact anything but a term indicating insanitary practices. Would anyone buy a “filthy” or “diseased” burger?