(AP)-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 in a statement that the U.S. Food and Drug Administration found salmonella heidelberg in two of six poultry houses that were tested at its production facility in Clarion during a routine inspection in May.

The company said the presence of the bacteria did not mean 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 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 Jack DeCoster, an egg magnate with a long history of food safety, labor and environmental violations. Centrum Valley Farms took over management of DeCoster’s operations in Iowa last year, vowing to improve them.

In an Aug. 14 warning letter from John Thorsky, director of FDA’s Kansas City regional office, the agency said it was concerned about the presence of salmonella heidelberg, or SH, in Centrum Valley Farms’ poultry houses, warning it could enter chickens’ organs and end up in their eggs.

Chief Operating Officer Steve Boomsma said in the statement that Centrum Valley was in the process of responding to FDA’s findings, which included several deficiencies in the company’s 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.”

Salmonella is the most common bacterial form of food poisoning, causing diarrhea, cramps and fever within days of eating a tainted product. It can be life-threatening. Salmonella heidelberg is a different strain than the more common salmonella enteritidis blamed for the 2010 outbreak. Investigators found both strains on DeCoster’s farms after the outbreak.

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.

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 U.S. under several 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 rules require mandatory testing for the bacteria at different stages of production. Companies that find salmonella in their poultry houses must either conduct additional testing over several weeks and destroy the bacteria or divert the eggs to nonfood use.

The FDA also said that Centrum Valley’s contract technician was not collecting enough samples for testing, that it had failed to maintain records showing compliance with refrigeration requirements, and that its salmonella prevention plan was incomplete.

The letter gave Centrum Valley 15 working days to outline its plans to correct the violations and prevent their recurrence.