By Michelle Watson and Nadia Kounang, CNN

(CNN) — McDonald’s will resume selling Quarter Pounders in all restaurants this week after considering new data regarding an E. coli outbreak linked to its famed burgers, the company announced Sunday.

The US Centers for Disease Control and Prevention issued a food safety alert Tuesday warning that dozens of people had reported eating the Quarter Pounder sandwich at McDonald’s before becoming sick.

The E. coli outbreak has led to at least 75 illness across 13 states, including 22 hospitalizations and one death, according to the CDC. Most of the illnesses were n Colorado.

A specific ingredient has not been confirmed as the source of the outbreak, but the US Food and Drug Administration said last week that the slivered onions or beef patties on Quarter Pounder sandwiches are the most likely source of contamination.

The US Department of Agriculture’s Food Safety and Inspection Service said Monday that evidence does not point to ground beef as the probable source of the E. coli outbreak.

“FSIS has conducted a thorough investigation in response to this outbreak, including traceback of beef patties served on Quarter Pounders at McDonald’s,” the agency said in a statement. “FSIS used specific meal information reported by ill people to trace beef patties through the supply chain to the establishment where they were produced and did not identify a beef source.”

On Sunday, the Colorado Department of Agriculture said that McDonald’s beef patties used for the Quarter Pounder tested negative for E. coli. The department tested fresh patties from restaurants associated with the outbreak.

Based on the findings from that testing and after comparing CDC data with its own supply chain data, McDonald’s is confident in ruling out fresh beef patties as a source of contamination, the company said in a Sunday news release.

It’s now asking beef suppliers to produce a new supply of fresh beef patties, and the Quarter Pounder is expected to be available in all restaurants in the coming week, the release said.

The 900 restaurants that received slivered onions from supplier Taylor Farms’ Colorado Springs facility will resume sales of Quarter Pounders without slivered onions, the release added. “Those restaurants are in Colorado, Kansas, and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, Oklahoma, and Utah,” it said.

The FDA, the USDA and the CDC say they are continuing to work with partners to investigate the source of the outbreak.

Taylor Farms removed yellow onions from the market “out of an abundance of caution,” the company said in a statement Wednesday, and distributor US Foods has issued a recall of four onion products due to “potential E. coli contamination.”

“I know that our relationship is built on trust,” McDonald’s US President Joe Erlinger said in a video message posted Sunday. “You trust us to serve you safe food every time.”

“On behalf of the McDonald’s system, I want you to hear from me: we are sorry,” Erlinger added. “For those customers affected, you have my commitment that, led by our values, we will make this right.”