Frank Yiannas, a top official at the Food and Drug Administration in charge of the agency’s food policy and response office, announced Wednesday that he is stepping down as deputy commissioner.

Yiannas was among the officials leading the FDA as it navigated its way through last year’s infant formula shortage after Abbott Laboratories voluntarily shut down production at the country’s largest formula factory following reports that infants who consumed formula from the plant got sick.

He resigned days after Abbott Laboratories confirmed that the Justice Department was investigating the company over its Michigan baby formula plant.

“Today, I informed Commissioner [Robert] Califf that I will be resigning my position as Deputy Commissioner for the Office of Food Policy and Response effective February 24,” Yiannas tweeted. “I am honored to have served the American public, alongside each and every one of you, over these past four years.”

Since December 2018, Yiannas has been involved in developing and rolling out policies related to food safety, including responses to outbreaks, tracing of foodborne illness investigations, product recalls and supply chain innovation.

An expert panel issued a scathing report last month about its investigation of the FDA’s processes and organizational structure for its foods program. The panel criticized, among other things, a “culture, structure, and governance model” that detracts from the program’s effectiveness.

FDA Commissioner Robert Califf ordered the investigation in July as criticism grew that the agency had mishandled the formula crisis after illnesses were reported.

Yiannas’ resignation letter, obtained by the The Washington Post, referred to having inherited a “decentralized structure” at the foods program he operated, which he said “significantly impaired FDA’s ability to operate as an integrated food team and protect the public.”

NBC News has asked Yiannas for comment.

In a statement, the FDA lauded Yiannas for his service on the agency’s leadership team, saying his efforts to tackle key initiatives helped “create a safer and more digital, traceable food system for our country.”

“The FDA remains committed to providing an update on steps to strengthen the Human Foods Program at the end of January and additional updates on the organizational structure, including how responsibilities of Mr. Yiannas’ position will be handled moving forward, by the end of February,” an FDA spokesperson said in a statement.