IOWA CITY, Iowa – A company that promised to clean up Iowa’s egg industry after a nationwide salmonella outbreak in 2010 said Friday that a recent government safety inspection discovered the bacteria in two of its barns and that it took steps to protect consumers.

Centrum Valley Farms said the U.S. Food and Drug Administration found the strain of bacteria known as salmonella heidelberg in two of six poultry houses that were tested at its production facility in Clarion, Iowa, during a routine inspection in May.

The company said the presence of the bacteria in the barns did not mean that any eggs were tainted, but that it nonetheless diverted an unspecified number from the market “in the interest of egg safety.”

The company said the eggs were withheld until they tested negative for the bacteria four times and were eventually approved for sale by the FDA.

The plant is under strict oversight because it was one of several in northern Iowa implicated in the 2010 outbreak, which led to the recall of more than 500 million eggs nationwide and sickened an estimated 2,000 customers.

During the outbreak, the plant was owned and controlled by Austin “Jack” DeCoster, an egg magnate with a long history of food safety, labor and environmental violations. Federal inspectors later discovered filthy conditions at DeCoster’s Iowa farms, including dead rodents and towers of manure.

Centrum Valley Farms took over management of DeCoster’s operations in Iowa in November 2011, vowing to improve them.

At the same time that DeCoster and his son, Peter, gave up control of their Iowa egg operations, they also handed over control of their operations in Ohio and Maine. A division of Minnesota-based Land O’Lakes Inc. took over three egg farms, in Leeds, Turner and Winthrop.

In an Aug. 14 warning letter to Centrum Valley Farms executives, the FDA said it was concerned about the presence of salmonella heidelberg or SH in Centrum Valley Farm’s poultry houses, warning it could enter chickens’ organs and end up in their eggs.

“SH has caused several egg-associated outbreaks resulting in human illness and at times death. Given this body of evidence, FDA considers SH within a poultry house environment to be a public health threat,” according to the letter from John Thorsky, director of FDA’s Kansas City regional office. “We acknowledge that you have been working with FDA to address this situation.”

Chief Operating Officer Steve Boomsma said in the statement that Centrum Valley was in the process of responding to FDA’s findings, which also included several deficiencies in its testing for salmonella and its salmonella prevention plan.

“Providing safe, high-quality eggs to Centrum Valley Farms customers is our obligation,” he said. “We have already taken corrective actions.”

In its letter, FDA noted that Centrum Valley had promised several improvements, and that its inspectors would be looking for verification of them during their next visit.

Iowa is by far the nation’s leading egg producer, with 50 million hens that produce about 14 billion eggs per year.

Centrum Valley hailed its takeover of DeCoster’s operations as a step toward repairing consumer confidence after the outbreak. It vowed to bring in new management teams to improve egg safety and compliance with environmental, animal care and disease prevention programs.

Centrum Valley says its eggs are sold at major retailers across the country under a variety of brand names, but it would not identify its customers. On its website, the company says that its “environmental testing and compliance procedures are over and above” those required by the FDA.

But the FDA said otherwise in its warning, which found “serious violations” of rules that went into effect in 2010 to prevent salmonella in the production, storage and transportation of shell eggs. The letter gave Centrum Valley 15 working days to issue a response outlining “specific things you have done or plan to do to correct these violations and prevent their recurrence.”WHAT IS SALMONELLA?

Salmonella is the most common bacterial form of food poisoning, causing diarrhea, abdominal cramps and fever within days of eating a contaminated product. It can be life-threatening.

Salmonella heidelberg, the strain that was detected in May at Centrum Valley Farms in Iowa, is a different strain than the more common salmonella enteritidis blamed for the 2010 outbreak. After the outbreak, federal investigators found the presence of both strains on egg magnate Austin “Jack” DeCoster’s Iowa farms, which were taken over in 2011 by Centrum Valley.