CLARION, Iowa – A recent inspection revealed Salmonella bacteria in two poultry barns implicated in an outbreak that sickened roughly 2,000 people and led to the recall of more than 500 million eggs in 2010.

Centrum Valley Farms said the US Food and Drug Administration (FDA) found Salmonella Heidelberg bacteria in two of six poultry houses during a routine inspection, according to the Associated Press. The company said the presence of the bacteria did not mean eggs were contaminated. However the company opted to withhold an unspecified number of eggs from the market on food safety concerns.

The eggs were tested multiple times, and the FDA eventually approved them for sale, according to AP.

The plant is under intense scrutiny because it was one of several egg production facilities implicated in the 2010 outbreak. Jack DeCoster owned and operated the facility during the outbreak, and Centrum Valley Farms took over management of the Clarion, Iowa, operation pledging to clean it up.