McDonald's selling Quarter Pounders again after E. coli outbreak linked to onions

After a brief hiatus, the Quarter Pounder is back on the menu in Oklahoma.

McDonald's announced Sunday that it would begin selling the burger again in Oklahoma and 11 other states after the Centers for Disease Control and Prevention said an E. coli outbreak sickened dozens of people and lead to one death.

More: McDonald's E. coli outbreak expands to 75 people. How dangerous is it?

An investigation showed the culprit was slivered onions produced by a Colorado Springs facility operated by Taylor Farms. McDonald's also temporarily halted distribution of beef patties, but tests showed they were not the source of the outbreak.

"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," the fast food restaurant chain said.

In the immediate future, Quarter Pounders in the affected regions will be served without slivered onions.

McDonald's E. coli recall affected 12 states

On Oct. 22, McDonald's halted sales of the Quarter Pounder at 900 restaurants in Colorado, Kansas, and Wyoming, as well as portions of Idaho, Iowa, Missouri, Montana, Nebraska, Nevada, New Mexico, Utah and Oklahoma.

People from 13 states reported illnesses to the CDC. McDonald's said that some restaurants were located inside airports, which may account for illnesses in additional states.

So far, no illness was recorded in Oklahoma. The CDC said the true number of sick people is likely much higher than the number reported because many people recover without medical care and are not tested for E. coli.

Several lawsuits against the company have been filed in the past week, alleging negligence, product liability, and other claims.

What is E. coli?

Escherichia coli is a bacteria that exists in food and water and in people's and animals' intestines, as a healthy part of the intestinal tract, the CDC said .

Different types of E. coli trigger different bodily responses. Some forms of the bacteria can make people sick.

In its update on the McDonald’s cases , the CDC said most infected people with Shiga toxin-producing forms of E. coli like the one found in these individuals experience severe stomach cramps, diarrhea that is often bloody and vomiting. In some cases, people develop serious kidney issues that require hospitalization.

Symptoms typically begin three to four days after consuming food or beverages containing the bacteria.

This article originally appeared on Oklahoman: McDonald's selling Quarter Pounders again after E. coli outbreak linked to onions