On July 14, the Centers for Disease Control and Prevention reported the outbreak as being from an “unknown source.” The CDC and the FDA did not identify lettuce at certain Taco Bell locations as a source until July 17. The same day, Taylor Farms issued a recall, and the FDA published the recall notice on July 18. The recall notice did not include details or clear information about how much lettuce was being recalled or where it had been shipped. An FDA report identified this week found that Taco Bell’s parent company received just 2.5 percent of the tainted lettuce, with the rest going elsewhere. Walmart received 46 percent of the recalled cases.

Warren’s letter also questioned confusion about the FDA reporting that Taylor Farms’ lettuce had tested positive for Cyclospora, only to retract the claim the next day, calling it a false positive. Taylor Farms then claimed the FDA had apologized to it, which the FDA quickly denied.

Warren posed a series of questions to Kennedy, including whether Taylor Farms or a Trump political appointee pressed the FDA to reevaluate the test result, leading to the retraction. She is also seeking transcripts, summaries, and notes from communications between federal agencies and Taylor Farms.

“[T]he specter of corruption—and quid pro quo politics—casts a darker shadow” over the outbreak response than simply dangerously bad food safety policies from the Trump administration, Warren wrote.

In a statement to The Hill, a Taylor Farms spokesperson said that the company “acts in the interest of science and consumer health, not politics. We categorically reject suggestions that we attempted to receive or received favorable regulatory treatment due to political contributions or other improper influence. Any such allegations are false.”

A Health Department spokesperson told the outlet that the federal government’s investigations into the outbreak “were not impacted by staffing changes or reductions in force. Political contributions or relationships have no bearing on FDA or CDC outbreak investigations.”