Cookie Dough Is the Culprit of E. Coli Outbreak

Just in time for holiday cookie season, a report says that eating raw, ready-to-bake cookie dough is unsafe.

A new study found that eating uncooked ready-to-bake cookie dough poses health risks. Photograph courtesy of Flickr user SuperFantastic

Hey, you! Drop the cookie dough.

We hate to be the Grinch this year, but it’s for your own good. You’ve heard it before, but it bears repeating: Eating uncooked cookie dough—even the ready-to-bake kind—is bad for you. Really bad.

An investigation of a 2009 multi-state E. coli outbreak found that the culprit was ready-to-bake commercial prepackaged cookie dough. Between March 16 and July 8, 2009, 77 people reported illness, and 35 were hospitalized. No one died.

A team of researchers then conducted a case-control study, in which 33 of 35 case patients ate raw, ready-to-bake cookie dough and a week later reported getting sick. Ninety-four percent of the patients consumed the same brand of cookie dough; 84 percent consumed a chocolate chip flavor, and 10 percent ate chocolate chip mixed with another flavor.

But the chocolate chips were not the source of contamination, the researchers found. A more likely source could be the flour used in the dough. “Low levels of salmonella contamination can occur in wheat flour, and flour and flour-based mixes have been implicated in food-borne salmonella outbreaks,” the authors wrote.

Though an FDA inspection team failed to identify a source and route of product contamination during an investigation at the cookie dough company’s plant, the study is an example of the very real health risks of eating raw products that are meant to be cooked before eating—a common practice among college students, and females in particular, the authors said.

In fact, during interviews for the study, “several patients reported that they bought the dough with the intention of only eating it unbaked; they had no plans to actually bake cookies.”

Maybe it’s time to dust off the baking sheets, after all.

For more information, read the full study in the Clinical Infectious Diseases journal.