All of the inspection reports are posted on a county website. But the county could be doing a lot more to publicize the results, said Doug Powell, a Kansas State University food safety professor who consults on the design of restaurant inspection systems.

"Online is a start, but lots of people don't have access at the time they make a dining decision -- when they walk in the door. That's why on-site disclosure is important to paying consumers," Powell wrote in an email.

Other central San Joaquin Valley counties vary in their practices.

None has a placard system like Sacramento or Los Angeles, although Madera County is considering one. Kings County issues silver stars, but only to restaurants that perform well on inspections and pass other food safety tests. Tulare County issues gold seals on similar criteria.

Kings County has posted inspection reports on its website since 2008. Tulare County sends weekly summaries to the Visalia Times-Delta newspaper, which posts them on its site. Madera does not post reports but hopes to start by the end of 2012, county Environmental Health Director Jill Yaeger said.

Fresno County's environmental health director, David Pomaville, joined the department only in December and said so far he hasn't seen a need to post inspection results at restaurants.

"I haven't drawn the conclusion that that is a tack that we would benefit from," Pomaville said. Instead, Pomaville says he is focusing his inspectors' attention on high-risk issues such as temperature control and sanitation.

In the past, Robinson said, the department's criticism of posting results on-site has centered on the fact that the inspection reflects a restaurant's condition at a single point in time. That, he said, might give diners "a false sense of security" when they go to the same restaurant on another day.

"At that moment they got an 'A' letter grade, and the next day they had sewage backing up, and it didn't change the letter grade," Robinson said.

Those kinds of concerns haven't slowed the momentum elsewhere toward posting inspection results on-site.

New York City began posting letter grades in 2010. One year later, a survey said 70% of the city's adults had noticed the signs, and of those 88% considered them when deciding where to eat.

Sacramento County last month marked its fifth year with a system of green, yellow and red signs and said major health risks found by inspectors had dropped 26% since the county began issuing the placards and requiring restaurants to post them.

Daniel Conway, legislative and public affairs director for the California Restaurant Association, said the Sacramento system has been well-received by restaurant owners, in part because inspectors are quick to do follow-ups when initial inspections result in something less than a green placard.

"It really comes down to the system and the ability of a restaurant to comply with it, as well as the message to the consumer," Conway said.

In the late 1990s, a television station's hidden-camera investigation showed shocking conditions in Los Angeles restaurants, including roaches, rat droppings, spoiled meat, rotten vegetables, and employees licking their fingers while preparing food. The Board of Supervisors implemented a letter-grade posting system two months later.

A group of researchers has done several studies of the Los Angeles system. In one of their most dramatic findings, the researchers compared reports of food-poisoning hospitalizations before and after the grading system was begun. They found that illnesses declined by 20% over the program's first three years -- but only in areas where grades were posted. Neighboring counties saw no such decline.