At least 104 people have been sickened, with 34 hospitalized, in an outbreak of E. coli food poisoning tied to onions served on McDonald's Quarter Pounder hamburgers, U.S. federal health officials said Wednesday.

Cases have been detected in 14 states, according to an update from the U.S. Centers for Disease Control and Prevention (CDC). One person died in Colorado and four people have developed a potentially life-threatening kidney disease complication.

At least 30 cases were reported in Colorado, followed by 19 in Montana, 13 in Nebraska, 10 in New Mexico, eight in Missouri and Utah, six in Wyoming, three in Kansas, two in Michigan and one each in Iowa, North Carolina, Oregon, Washington and Wisconsin.

Illnesses were reported between September 12 and October 21. At least seven people who got sick said they ate McDonald's food while traveling.

Slivered onions served on the Quarter Pounders were the likely source of the outbreak, the CDC said. Taylor Farms, a California-based produce grower, recalled onions potentially linked to the outbreak. Tests by the U.S. Food and Drug Administration detected a type of E. coli bacteria that produces a dangerous toxin in one sample of the onions, but it did not match the strain that made people sick, officials reported.

Quarter Pounders were removed from menus in several states during the early days of the outbreak. The onions served at the McDonald's locations are past their shelf life and no longer for sale. CDC officials said the risk to the public remains low.

The type of bacteria implicated in this outbreak causes about 74,000 infections in the U.S. annually, leading to more than 2,000 hospitalizations and 61 deaths each year, according to the CDC.

Symptoms occur quickly, within a day or two of eating contaminated food, and typically include fever, vomiting, diarrhea or bloody diarrhea and signs of dehydration – little or no urination, increased thirst and dizziness. The infection can cause a type of serious kidney injury, especially in kids younger than 5. E. coli poisoning in young children requires immediate medical attention.