Foodborne illness outbreaks are fairly rare for well-known restaurant chains, but they do happen. This week, an outbreak of E. coli food poisoning linked to McDonald’s Quarter Pounder hamburgers sickened at least 49 people in 10 states, including one person who died and 10 who were hospitalized. McDonald’s has halted distribution of chopped onions and temporarily removed the Quarter Pounder from menus in several states.

Here’s a brief history of some recent incidents that have sickened customers, disrupted businesses, and sometimes changed the way food safety is regulated in the United States.

Wendy’s

Wendy’s removed lettuce from sandwiches at its restaurants in Michigan, Ohio and Pennsylvania in August 2022 after some people reported getting sick. The Centers for Disease Control and Prevention said at the time that it was trying to determine whether romaine lettuce was the cause of an outbreak of E. coli. coli that sickened at least 37 people and whether romaine lettuce used at Wendy’s was also served or sold at other businesses. One person also became ill in Indiana, according to the CDC.

Chipotle

In 2015, Chipotle was hit by an outbreak of E. coli that sickened more than 50 people and temporarily closed dozens of restaurants on the West Coast, but that was just the beginning. A month later, 30 Boston College students, including at least eight members of the men’s basketball team, complained of gastrointestinal symptoms after eating at a Chipotle restaurant.

Federal authorities declared the outbreak over in February 2016, but the chain closed each of its restaurants to retrain employees and allow them to regroup. However, at the end of the year, Chipotle co-CEO Montgomery Moran resigned as sales fell. In 2020, Chipotle Mexican Grille agreed to pay a record $25 million fine to resolve criminal charges that it served tainted food that sickened more than 1,100 people in the United States between 2015 and 2018.

The company admitted that poor safety practices, such as failing to store food at appropriate temperatures to prevent the growth of pathogens, had made customers sick in Los Angeles and nearby Simi Valley, as well as Boston, Sterling, Virginia, and Powell, Ohio. Today, Chipotle is among the most successful restaurant chains in the United States, with sales of nearly $10 billion last year.

Taco Bell

In December 2006, Taco Bell ordered the removal of scallions from its 5,800 restaurants nationwide after samples taken by investigators appeared to contain a severe strain of E. coli. coli. The outbreak has sickened at least 71 people in New Jersey, New York, Pennsylvania and Delaware, with most of them hospitalized, according to the CDC.

Eight people developed a type of kidney failure called hemolytic uremic syndrome. Eventually, contaminated lettuce was determined to be the likely cause, with the vegetable being used in many menu items.

Almost immediately, Taco Bell launched a newspaper advertising blitz and sent its president on a series of media interviews to assure customers that its food was safe. Taco Bell has fully recovered and its sales jumped 6% last year as the company opened more than 200 new locations.

Jack in the box

Four deaths and more than 700 illnesses in Washington, Idaho, California, and Nevada between 1992 and 1993 were ultimately traced to undercooked hamburgers at Jack in the Box restaurants contaminated with E. coli. The ensuing investigation by federal regulators changed regulatory practices in the United States, experts say.

An investigation by the CDC identified five slaughterhouses in the United States and one in Canada as likely sources of animals used in contaminated meat batches and identified potential control points to reduce the likelihood of contamination. Animals slaughtered in domestic slaughterhouses have been traced to farms and auctions in six Western states. No slaughterhouse or farm has been identified as the source.

The U.S. Department of Agriculture has mandated a Hazard Analysis and Critical Control Point system, which helps identify and control hazards within the food production system. The system provided for more surveillance and controls to quickly limit the spread of epidemics. Jack in the Box lost more than $44 million in 1993 and made no annual profit for another three years. The company has fully recovered and reported revenue of $1.7 billion last year, its third straight year of double-digit sales growth.