The San Diego County Board of Supervisors voted unanimously Tuesday to study whether food trucks can be required to display the same health inspection letter grades as restaurants.The county inspects around 1,100 mobile food operations in the region, of which 550 sell to the public, but they are not required to display the results, Supervisor Ron Roberts said. Restaurants generally display their blue "A" grade on a placard in a front window.The food trucks would receive decals instead of cards so that the grades could not be transferred among vehicles."What we're concerned with -- it's not the mobile units that maybe sells packaged potato chips or candy bars and things of that sort. It's the mobile food units in which they either prepare food or have to have refrigeration to make sure the food is maintained or that the hygienic conditions come into play," Roberts said.County staff is due to report back within four months on whether an ordinance is feasible."We're already inspecting these trucks, so I don't want anybody in the public to panic and think anything is unsafe," Roberts said. "What will change is you will know what that rating is, you will know when it was inspected."Roberts said his idea is supported by the San Diego County Restaurant Association and the owners of Trucked Up Productions, which operates the Chop Soo-ey and Ms. Patty Melt food trucks.Roberts said the letter grades for restaurants and mobile food facilities will be posted online by the end of this year.