The E. Coli outbreak at McDonald’s was worse than we thought

The reach of McDonald’s E.coli the outbreak has grown. Health officials have reported a significant increase in cases this week, with many more likely going undetected.

First, the U.S. Centers for Disease Control and Prevention reported the outbreak in late October, which initially affected at least 49 people in 10 states. As of the latest update from the CDC issued As of Wednesday, there have now been 104 cases in 14 states, while 34 people have been hospitalized and one person has died.

While more cases may come to light, the likely source of the outbreak has been identified – fresh cut onions – and officials have said the danger from these contaminated onions has likely passed. But while this episode is largely over, it does highlight that such outbreaks can quickly spiral out of control, perhaps aided by the complexity of production and distribution practices within fast-food chains. Inadequate or poor quality control may be another factor.

Health officials initially found a link between these cases and McDonald’s Quarter Pounder menu item. But suspicion quickly turned to the fresh chopped onions that are used exclusively on the sandwich. The CDC ultimately confirmed that the outbreak was caused by onions delivered from the Taylor Farms company. Some fast food chains temporarily drawn their own onion products in response and Taylor Farms issued a larger recall for its onion products, although no further cases appear to have occurred outside of McDonald’s.

Many types of harmful E.coli can cause unpleasant, albeit short-lived, gastrointestinal symptoms. But the strain behind this outbreak, O157:H7, produces toxins that can increase the risk of more serious, life-threatening complications, such as hemolytic uremic syndrome (HUS), which can cause major organ damage, especially to the kidneys. Four cases of HUS have been identified, although the only death reported so far was not among them.

It is certainly possible that more cases will be reported. In general, foodborne outbreaks are often much larger than they appear because only a small percentage of people become sick enough to seek outside medical care. It can also take an average of three to four weeks for health officials to determine whether someone’s foodborne illness is linked to an existing outbreak. But most cases of this outbreak occurred before the CDC’s reporting and subsequent removal of onions from the McDonald’s menu. And because the contaminated lots have been recalled and/or have now exceeded their expiration date, the current risk of further E.coli of this specific contaminant is probably zero.

Within a week of the outbreak being first publicized, McDonald’s returned the Quarter Pounder on the menu, without onions. More recently, after finding a new supplier, the chain also bought back fresh chopped onions — a move that appears to have the blessing of health officials.

“At this time, there does not appear to be any ongoing food safety concerns associated with this outbreak at McDonald’s restaurants,” the Food and Drug Administration said in the newly released statement.

While things may have calmed down for Quarter Pounder fans, the fallout for McDonald’s isn’t necessarily over. Several alleged victims of the outbreak have remained legal representation or already started suing the restaurant chain because of their food poisoning.