-- Shares Facebook Twitter Reddit Email McDonald's is bringing back its Quarter Pounders to all restaurants this week amid an ongoing E. coli outbreak traced to ingredients in the fast food chain’s famed burger. The outbreak has sickened at least 75 people across 13 states, the Centers for Disease Control and Prevention (CDC) reported Friday.

One person has died. During a media briefing on Sunday, McDonald's confirmed that the beef used in its Quarter Pounder patties is not the source of contamination in the ongoing outbreak. Testing conducted by the Colorado Department of Agriculture found that samples of the beef tested negative for E.

coli, USA Today reported . “The issue appears to be contained to a particular ingredient and geography, and we remain very confident that any contaminated product related to this outbreak has been removed from our supply chain and is out of all McDonald’s restaurants,” Cesar Piña, McDonald's Chief Supply Chain Officer, North America, said in the statement. McDonald's Quarter Pounders will be served without slivered onions, which were supplied by California-based producer Taylor Farms.

Last Thursday, Taylor Farms issued a recall for whole and diced onions over possible E. coli contamination, food service distributor US Foods announced . A Food and Drug Administration (FDA) investigation is currently underway at Taylor Farms’ Colorado Springs facility.

Related CDC links E. coli outbreak to McDonald’s Quarter Pounders, one dead Nin.