An inspection at the Abbott Laboratories facility in Sturgis, Michigan found harmful bacteria on surfaces in some areas of its powdered baby formula production, the U.S. health regulator said on Tuesday.

Complaints that the facility’s products had caused bacterial infections forced Abbott to recall certain Alimentum, Similac, and EleCare baby formulas last month, prompting a probe from the U.S. Food and Drug Administration (FDA), as previously informed.

The inspection from Jan. 31 to March 18 showed that Abbott did not have a control system covering all stages of processing to prevent microbe contamination of infant formula.

Personnel working with infant formula also did not wear necessary protective apparel, the FDA said.

Abbott said in a statement:

We’re taking this very seriously and are working closely with the FDA to implement corrective actions.

No Cronobacter sakazakii was found during the company’s testing of products that were distributed to consumers, Abbott added.

The company also said that the genetic makeup of the Cronobacter sakazakii found at the Michigan plant did not match that of the reported cases.

Cronobacter sakazakii bacteria can cause serious invasive infections and premature infant death.