The McDonald’s E. coli outbreak has now sickened more than 100 people

The number of E. coli cases linked to onions used by McDonald’s has cracked 100. The Food and Drug Administration said in an update that the number of people sickened by the fast food bacteria outbreak has climbed from 90 to 104.

“Of 98 people with information available, 34 have been hospitalized, and 4 people developed HUS, a serious condition that can cause kidney failure,” the agency said. “One death has been reported from an older adult in Colorado.”

The FDA says that E. coli are generally harmless bacteria, but ingesting the wrong kinds from contaminated food or beverages can lead to a severe gastrointestinal disease: “Generally, the symptoms include severe stomach cramps, diarrhea, fever, nausea, and/or vomiting,” it warns.

Food safety concerns have been a prominent issue lately. Experts believe that a combination of lax oversight and cost-cutting have led to more people getting sick, such as with listeria outbreaks that have also been all over recent headlines.

When people started getting sick eating its famous Quarter Pounder burgers, McDonald’s rushed to figure out what was going on. It quickly established that beef wasn’t the culprit, which is good because it would have had significant implications for the rest of the company’s menu.

Then, the Centers for Disease Control and Prevention zeroed in on yellow onions from McDonald’s supplier Taylor Farms as the cause. The onions are slivered and served on Quarter Pounders. The company said it is no longer sourcing onions from Taylor Farms.

Now, McDonald’s is trying to get customers back in its restaurants after the outbreak. On an earnings call last month, CEO Chris Kempczinski said that the journey will be difficult emotionally as well as fiscally.

“Hearing the reports of how this has impacted our customers has been wrenching for us,” he said.

Quartz’s Francisco Velasquez and Bruce Gil contributed to this article.