Grade pending: the effect of the New York City restaurant sanitary grades inspection program on Salmonellosis

New York City began public reporting of restaurant sanitary inspection grades in 2010. The policy’s impact on the incidence of foodborne illness has not been previously studied. We used a retrospective cohort design to evaluate whether the introduction of sanitary grades in 2010 reduced the incidence of Salmonellosis. To estimate the policy impact, we performed a difference-in-differences analysis in which in New York City was compared to a “synthetic control group” consisting of a weighted sample of comparison geographies. We evaluated reported Salmonellosis cases from April 2003 through December 2015 from the National Notifiable Diseases Surveillance System (NNDS) (National Notifiable Diseases Surveillance System, Weekly Tables of Infectious Disease Data n.d.). Our main outcome measure was quarterly risk-adjusted cases of reported Salmonellosis per 100,000 residents. Results of our difference-in-differences analysis found that the New York City restaurant sanitary grades program was associated with a non-significant reduction in risk-adjusted cases of reported Salmonellosis per 100,000 (−0.31, 95% confidence interval = (−1.41, 0.80)). This finding was robust across all specifications. Consistent with recent evidence that public reporting has had little impact on public health, public reporting of restaurant sanitary inspection grades did not appear to decrease the incidence of Salmonellosis.