E.coli Found in Ready-to-Bake Cookie Dough

Raw packaged dough contaminated with bacteria strain

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Say it ain't so: ready-to-bake cookie dough has been identified as the culprit of an E.coli outbreak that sickened 77 raw cookie dough lovers.

Let's not pretend that this couldn't happen to us. It's not uncommon to bring home a package of ready-to-bake cookie dough from the store and have it mysteriously “disappear” before the cookies have even had the chance to get in the oven.

A new study investigating the source of a May 2009 E.coli outbreak drives home the point that ready-to-bake cookies are meant to be baked before eating.

"Don't eat raw pre-packaged cookie dough, bake it first."

The report was led by Karen Neil, MD, MSPH, and her colleagues at the Centers for Disease Control and Prevention and at state health departments. The 2009 outbreak led to a nationwide recall of Nestle Toll House refrigerated cookie dough in June.

The study offers recommendations to prevent a similar outbreak from happening again. The number one piece of advice? Bake your cookies before you eat them.

The alternative is that manufacturers reformulate their product so that it can be safely eaten by consumers, and/or educate their consumers that the dough is not safe to eat raw.

Dr. Neil and her colleagues detail the process of tracking down the source of the outbreak. Ground beef, leafy green vegetables, sprouts, and melons, among others, were all investigated. It took some digging for the pattern to emerge that all of the sickened patients had consumed raw pre-packaged cookie dough.

The study authors suspect that one of the ingredients of the cookie dough was contaminated with a strain of E.coli. They were not able to conclusively pinpoint the culprit, but flour is the prime suspect. Flour does not generally undergo a step to kill pathogens, unlike pasteurized eggs and other ingredients.

While not as common, heat-treated or pasteurized flour does exist. Following the 2009 outbreak, a few manufacturers notified the FDA that they have switched over for their cookies.

Despite the dangers, it might be difficult to convince raw dough lovers to stop consuming these unbaked treats. Several of the people interviewed in the study said they bought the ready-to-bake cookie packages without intending to bake them.

The study was published in Clinical Infectious Diseases in December 2011.

Reviewed by: 
Review Date: 
December 8, 2011
Last Updated:
December 11, 2011