New federal safeguards that officials say might have prevented the recent salmonella poisoning and massive egg recall had their genesis in research on Lancaster County egg farms 20 years ago.

Those controls are based on model controls long used to guard against egg contamination in Pennsylvania, the largest egg producer in the Northeast.

Pennsylvania's program, in turn, came about after two years of groundbreaking research into the sources of salmonella on Lancaster County egg farms.

Human cases of salmonella enteritidis have risen to 1,300, and more than a half-billion eggs have been recalled from two large egg producers in Iowa. Federal investigators said Thursday that contaminated chicken feed was at least one source.

Millions of Americans are thinking twice about ham and eggs for breakfast although they have been assured that they won't get salmonella with proper preparation and cooking precautions.

At a press conference on the scare earlier this week, Dr. Margaret Hamburg, head of the U.S. Food and Drug Administration, said new "egg rules" that went into effect for large egg producers on July 9 might have prevented the outbreak had they been in place earlier.

Those new rules require measures aimed at preventing the bacteria at 80 percent of the egg producers in the United States. The remaining egg producers must have them in place by 2012.

In contrast, the Pennsylvania Egg Quality Assurance Program has been in place since 1992. Though voluntary, the tough standards cover about 71 percent of the laying hens in the state.

In the 1970s and 1980s, Pennsylvania and the nation's egg industry were hit with a series of salmonella outbreaks.

Reports of salmonella enteritidis to the U.S. Centers for Disease Control and Prevention increased sixfold nationwide from 1976 to 1986.

The bacteria struck three Lancaster County poultry businesses in 1990. In 1991, salmonella was found in the laying houses of a Dauphin County facility owned by Manheim-based Kreider Farms.

The egg giant's eggs were banned in New York state after they were suspected as the cause of an outbreak of intestinal illness on Long Island.

"Pennsylvania's egg producers didn't want to sell eggs that would hurt people, so they got very aggressive about reducing salmonella enteritidis on their farms," said Paul Patterson, professor of poultry science at Penn State University.

During a two-year study that began in 1990, Penn State researchers descended on poultry farms in Lancaster County, the state's top egg producer.

They took swabs of coatings on farm machinery, egg conveyor belts and manure pits below the rows of laying hens.

"They would catch mice and test them," recalled Patricia Dunn, a veterinarian and senior research associate at the Penn State Animal Diagnostic Laboratory. "They honed in on the risk factors."

Rodent control by making sure hen houses were tightly sealed emerged as a key safeguard. Other recommended steps included testing baby chicks coming onto farms and vigilant testing of the hen houses for the presence of the bacteria.

Facilities in which even a trace of salmonella was found should be cleaned and disinfected, and any eggs found with the bacteria should be discarded or sent for pasteurization.

Those recommendations were quickly adopted as the Pennsylvania Egg Quality Assurance Program.

The precautions were embraced by the state's egg producers, and results were immediate.

In 1992, 38 percent of Pennsylvania flocks tested positive for salmonella. Today, about 8 percent test positive at some point. And hen houses found with the bacteria have dropped from 26 percent in 1992 to 1 percent today, according to Patterson.

About 1.2 eggs per 10,000 tested is found with salmonella today.

Many states followed Pennsylvania's lead. Now the federal government has too and apparently wishes it had acted sooner.

Lancaster County's large egg producers, such as Kreider Farms, Esbenshade Farms and R.W. Sauder, in recent days have proudly noted their participation in the state program on websites that address the salmonella scare.

None of those firms' eggs have been recalled.

In fact, their egg production has gone into high gear, as they send eggs to other parts of the country where 37 brands, so far, have had to recall eggs purchased from the Iowa farms.

acrable@lnpnews.com