One person has died and dozens have fallen sick from E. coli food poisoning linked to McDonald's Quarter Pounder hamburgers in several US states, federal health authorities said on Tuesday.

The outbreak — which began in September — has spread across 10 western states with at least 49 infections being reported, the US Centers for Disease Control (CDC) said.

"Epidemiologic data show that Quarter Pounder hamburgers served at McDonald's are contaminated with E. coli and are making people sick," the CDC said.

The highest number of cases are concentrated in Colorado and Nebraska. Other affected states include Iowa, Kansas, Missouri, Montana, Oregon, Utah, Wisconsin and Wyoming.

According to the CDC, ten people have been hospitalized — including one child with serious kidney complications.

"One older person in Colorado has died," the CDC added.

Most recall eating Quarter Pounders

All the people questioned in connection with the infections reported eating at McDonald's before they fell ill.

Most of them mentioned eating the popular Quarter Pounder hamburger, the CDC said.

The bacterial strain in question, E. coli O157:H7, can cause serious illness. It was also the source of a 1993 outbreak when four children died after eating undercooked hamburgers at Jack in the Box restaurants.

"Early information from FDA [Food and Drug Administration] indicates onions may be a source of this outbreak. Investigators from all agencies are working quickly to determine the contaminated ingredient," the CDC said.

What did McDonald's say?

McDonald's share price plummeted more than 6% in extended trading after the world's largest food chain was linked to the E. coli outbreak.

"Food safety is so important to me and everyone at McDonald's," the president of  McDonald's USA, Joe Erlinger, said in a video message.

The company has suspended the distribution of the slivered onions and temporarily taken the Quarter Pounder off the menu in affected regions.

Additionally, the Quarter Pounder has also been temporarily taken off the menu in parts of Idaho, Nevada, New Mexico and Oklahoma.

"We've taken steps to proactively remove slivered onions, which are used in Quarter Pounders, in select states," Erlinger said

"We've also made the decision to temporarily remove the Quarter Pounder from restaurants in select states" he added.

dvv/zc (AP, AFP, Reuters, dpa)