SILVER SPRING, MD. — A Quaker Oats Co. production facility closed after a recent product recall may have been contaminated with Salmonella for four years, the Food and Drug Administration said in a warning letter to parent company PepsiCo, Inc.

In the June 12 letter to PepsiCo, released July 9, the FDA said it found the presence of Salmonella Cubana at Quaker’s ready-to-eat granola bar and cereal manufacturing plant in Danville, Ill., during an inspection of the facility from Dec. 19, 2023, to Feb. 2, 2024. Chicago-based Quaker had announced a voluntary recall of certain granola bars and cereals on Dec. 15, citing potential Salmonella contamination, and then on Jan. 31 said it expanded the recall to include additional cereals, bars and snacks that may have been affected.

Quaker had tested Chewy granola bars from the Danville plant in late November, with samples positive for Salmonella later confirmed at a PepsiCo lab in December, leading to the product recall days later, according to the FDA. The agency said that, in its ensuing inspection, a food residue sample collected from a crack in the floor at the facility tested positive for Salmonella in an FDA analysis, and the company was notified of the finding in a Jan. 3 conference call.

“You acknowledged that you had identified historical isolates of Salmonella Cubana in your facility since at least 2020,” the FDA said in its June 12 letter to PepsiCo. “These findings may indicate that the same strain of Salmonella Cubana has survived since 2020.”

Also in the letter, the FDA said the company had found Salmonella Cubana in 13 environmental samples from the Danville plant since June 2022. The FDA said that on April 3 it received notice from the company that it planned to permanently close the Danville facility. On that date, the city of Danville announced that PepsiCo planned to shut the Danville production site effective June 8 after 65 years in operation.

The FDA also urged the company to consider taking further efforts to ensure food product safety.

“Although you intend to cease operations at the Danville facility, you have other manufacturing facilities and should evaluate if similar corrective actions are necessary in your other plants to reduce the likelihood of contamination,” the agency said in the letter.

When asked on July 12 for comment on the FDA’s June 12 warning letter, Quaker Oats Co. said it has taken action on the situation.

“Based on findings discovered at the Quaker facility located in Danville, Ill., we took immediate steps to ensure consumer safety, permanently closed the site, and we are decommissioning all the equipment,” Quaker said in a statement. “No other facilities have been found to have these same issues, and the warning letter has no relation to products currently in the market.”

In reporting second-quarter earnings on July 11, Purchase, NY-based PepsiCo said Quaker Foods North America continues to feel the impact of the product recalls but is making strides in resuming the production of affected items and expects the sales hit to soften over the balance of the year. For the quarter ended June 15, Quaker Foods posted year-over-year decreases of 18% in net and organic revenue, 4% in volume and 34% in operating profit.

“Quaker, you’re all familiar with the situation,” Ramon Laguarta, chairman and chief executive officer of PepsiCo, told analysts in a conference call. “We’re recovering the supply chain. By Q4, we’ll be in almost 100% supply. And, obviously, the business at that point will be growing materially because we’re just refilling the shelves on the pipeline. So that should be out of the picture, and it will be a positive impact for us.”