(CBS) Ever sneak a bite of the raw cookie dough log living in your refrigerator? You might be seriously risking your health, according to a new study.
"Raw cookie dough is not ready to eat, it is ready to bake," study author Dr. Karen Neil, epidemic intelligence service officer for the CDC, told WebMD.
For the study, published in the Dec. 8 issue of Clinical Infectious Diseases, researchers looked back at a 2009 outbreak of E. coli infection that sickened 77 people in 30 states, 35 of which were admitted to hospitals. Further investigation at the time determined that 33 out of the 35 hospitalized patients ate raw cookie dough.
The study authors said eating uncooked cookie dough "appears to be a popular practice," especially among teenage girls, and said some of the patients from the 2009 outbreak bought cookie dough with no intention of actually baking it. Symptoms of E. coli infection include bloody diarrhea, cramps, nausea, and vomiting.
The outbreak resulted in a recall of more than 3.5 million packages of cookie dough, however scientists didn't know for sure what caused the cookie dough to become contaminated because it was the first time E. coli had been linked to the tasty treat. Ground beef and leafy greens are usually the culprits behind foodborne E.coli outbreaks.
As part of their investigation, Neil and her colleagues reviewed data and came to a prime suspect that could have tainted the cookie dough: A contaminated batch of flour.
The researchers pegged flour because it doesn't undergo a "kill step" to get rid of possible pathogens, unlike other ingredients found in dough such as pasteurized eggs, margarine, and molasses.
"So we've never conclusively implicated flour but, kind of, that is what we suspect could have been the cause of contamination in the cookie dough product," Neil told the, adding that the flour manufacturer in question has switched to heat-treated flour.
Neil and her colleagues are calling on all cookie dough manufacturers to consider reformulating their product with pasteurized or heat-treated flour so it's ready-to-eat right out of the tube. Several companies, including Nestle have already made the switch, according to WebMD.
Fans of cookie dough ice cream can rest easy. Neil told MSNBC that cookie dough used in ice cream is manufactured as a "ready-to-eat product."
The bottom line?
"As tempting as it is to sample cookie dough, do not veer from the recommendations on the package," Dr. David Hirschwerk, an infectious disease doctor at North Shore University Long Island Jewish Hospital in Manhasset, N.Y., told WebMD. "If the package says you should cook it, then you should cook it."