County health officials said a study shows food-borne diseases have been reduced 13.1 percent because of the restaurant inspection and letter grading system imposed in 1998.

Dr. Jonathan Fielding, the county’s public health director and an author of the study, said it was the first scientific proof that the grading system resulted in a "demonstrable public health benefit."

"What’s really important here is we were able to show a reduction in hospitalizations due to food-borne illnesses, compared to state trends," Fielding said.