Blame the Untreated Flour in Cookie Dough for Making You Sick


Pasteurized eggs, margarine, sugar, baking soda, and molasses all go through processes to kill pathogens that could make consumers ill.

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Eating a couple of bites of cookie dough is just part of the fun of baking cookies, right? Well, as it turns out, doing so may increase your risk of getting sick with a foodborne illness.

A report published in the journal Clinical Infectious Diseases found that the 2009 Shiga toxin-producing Escherichia coli (STEC) outbreak that occurred in many states and hospitalized 35 people was caused by prepackaged ready-to-bake cookie dough, the kind found in your local grocery store. As a result 3.6 million packages of cookie dough were recalled and changes were made in the way companies manufacture cookie dough.

Researchers at the Centers for Disease Control who investigated the outbreak were never able to pinpoint the exact ingredient that caused the rash of illnesses; however, Dr. Karen Neil, the CDC study author, and colleagues said they believe the culprit was flour.

Unlike pasteurized eggs, sugar, baking soda, margarine, and molasses, flour does not usually go through a process to kill pathogens. Contaminated chocolate was also determined not to be a cause since the consumption of a chocolate chip variety of cookie dough was less strongly associated with illness compared to consumption of any other cookie dough.

The report released by the CDC arrived at two important conclusions: One is that companies that manufacture cookie dough should reformulate their product and make it as safe to eat as a ready-to-eat product. And two, that consumers need more effective education about the hazards of consuming unbaked products.

The study authors concluded that "foods containing raw flour should be considered as possible vehicles of infection of future outbreaks of STEC." The authors recommended that food manufacturers should consider using either heat-treated or pasteurized flour in foods that are ready-to-cook or ready-to-bake because they may be consumed before they are cooked or baked. Many food manufacturers have already done this.

Eating cookie dough is a popular practice despite label warnings against it. In fact, the study authors found that many of the patients treated for E. coli in 2009 said they bought the dough with no intention of ever baking it. They just planned to eat it uncooked. This underscores the likelihood that label statements and even education directed at consumers may not be enough to deter people from eating uncooked cookie dough, so making it as safe as possible may be the best solution.

The study was published online on December 8, 2011, in Clinical Infectious Diseases.

Image: Graça Victoria/Shutterstock

This article originally appeared on, an Atlantic partner site.

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Beth Fontenot is a registered dietitian and a licensed dietitian/nutritionist. She serves on the Louisiana Board of Examiners in Dietetics and Nutrition and writes for

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