The study, conducted by professors from Indiana University, Ball State University, and Villanova University, measured the effects of the minimum wage each time Seattle increased it and concluded that every dollar increase in the minimum wage resulted in total health code violations increasing by 6.3%.
http://www.npr.org/2017/09/13/550607377/how-the-minimum-wage-affects-restaurant-hygieneBlue code violations constitute "things like — insect, rodents, animals, employee cleanliness and hygiene; toilet facilities — whether they were properly constructed, supplied and cleaned; the garbage has been properly disposed of,"