Restaurant inspection grades do not reduce rates of foodborne illness – not in any scientifically credible and measurable manner.

Publicly available grades, like the A, B, C of LA and New York City, or the red, yellow, green of Toronto do increase public awareness and discussion of food safety, enhancing the overall food safety culture for staff and patrons.

I understand the desire to say, hey, this program made fewer people sick, but we’re not there yet, so why overstate when it will only lead to disappointment (also valid in budget estimates and personal relationships, and pretty much everything).

The International Business Times reports New York restaurant-goers are eating up the city’s three-year-old grading system, but its effect on public health is still a bit of a mystery taste test.

Salmonella infections in New York City rose more than 4 percent in 2012 to 1,168 cases, up from 1,121 cases the year before, according to the city’s Department of Health and Mental Hygiene. The uptick follows a much-publicized 14 percent decline in salmonella infections in 2011, the first full year that the letter grades were implemented. City officials had touted the initial decline as an early sign that the letter-grade posting may be contributing to a reduction in foodborne illnesses.

According to city health officials, the annual number of salmonella infections is a useful indicator of trends in food-related illnesses: Salmonella cases occur relatively frequently and about 95 percent of them are believed to be caused by eating contaminated food.

New York’s letter-grading system — in which restaurants are required to display a large A, B or C grade in the window of their establishment — was instituted in July 2010. Since that time, the Health Department has published a progress report every six months, updating New Yorkers on the system’s effectiveness. But those reports stopped coming after 18 months: the last one was published in January 2012.

Asked why the reports stopped, the Health Department told International Business Times that city officials “continue to evaluate the letter-grading initiative and are looking at the impact of the improved inspectional program on restaurants and on hospitalizations and emergency visits for foodborne illnesses.”

While popular with the public, the grading system has been described as unnecessarily burdensome and even humiliating by restaurant owners and food handlers who complain of steep fines, arbitrary inspections and bloated hearings procedures.

Patti Jackson, a veteran New York chef, said, “The grades are punitive and silly, but I don’t think they’re the worst thing that’s ever happened. They’re just a giant throbbing pain in the ass.”

Maybe. Or maybe the grades hold people a little more accountable. How best to improve the system?