Walk into any Los Angeles restaurant and you're likely to see a card in the window with a letter grade for its most recent health inspection.

In Sacramento, you can find a green, yellow or red sign with the same kind of information.

In Fresno County, you'll see nothing of the sort.

To find out how a restaurant in this county did on its most recent inspection, you have to screw up your courage and ask its staff for a copy. Or you can go to a little-publicized county website several weeks later and look it up.

It's easier elsewhere.

Los Angeles County began issuing letter grades and requiring restaurants to post them in 1998.

Over the next three years, hospitalizations for food-borne illnesses declined 20%, a subsequent academic study reported. Restaurants got higher average inspection scores after their grades were posted. Restaurants with the highest scores got more business on average.

Sacramento's program began five years ago and boasts of similar success, as well as support from local restaurateurs.

Despite those possible benefits, Fresno County health officials continue to resist the idea of posting inspection results on-site. Local restaurant owners are hesitant as well, an industry spokeswoman says.

"It's something that our members have not been in favor of," said Amalia Chamorro, director of local government affairs in Fresno for the California Restaurant Association.

More than 15,000 food facility inspections were conducted last year by Fresno County's division of environmental health.

Its 22 inspectors try to inspect restaurants four times per year (Sacramento and Los Angeles counties do three inspections per year) and bars twice per year. They check a long list of things that, if done wrong, can lead to food poisoning.

Do employees have a place to wash their hands, with hot water, soap and towels? Is cold food stored at 41 degrees or below and hot food at 135 degrees or higher?

Are the dishes and counters clean and chemically sanitized? Is the sewage system working right? Is the place free from vermin such as rats and cockroaches?

Each inspection results in a rating: either "in compliance," "minor violations," "significant violations, reinspection required," or "imminent public health hazard."

Last year, roughly one in four unannounced routine inspections resulted in an "in compliance" rating. Slightly more than half were "minor violations." One in five found "significant violations" warranting reinspection.

Of almost 12,000 routine inspections in 2011, only 12 found an "imminent public health hazard" -- a rating that generally results in closure. Most were due to water outages or sewer backups.

Other major violations only rarely result in a closure order.

The San Joaquin Country Club went three weeks with a heavy cockroach infestation early last year but never got an "imminent public health hazard" rating and was closed only once, overnight.

One time, an inspector's supervisor allowed the kitchen to remain open and finish serving a large group despite "live cockroaches in all different stages of life cycle." (Club manager Mike Carroll, hired in mid-November, said he has addressed the kitchen's roach problems as well as violations for too-warm refrigerators.)

What rating a restaurant receives depends partly on the inspector's judgment and partly on whether certain high-risk violations were found, which can be a judgment call as well, said Michael Robinson, a supervisor in the environmental health division.