Science-- there's something for everyone

Saturday, December 17, 2011

Don’t eat raw cookie dough



Just when you were congratulating yourself on saving time on your holiday baking, news that prepackaged raw cookie dough can make you ill. Karen Neil and her colleagues from the Centers for Disease Control (CDC) linked 77 cases of Escherichia coli O157:H7 back in 2009 to ready-to-bake commercial cookie dough. Luckily, none of the afflicted people died, though several had to be hospitalized.

I had heard that you should not consume raw cookie dough in order to avoid the Salmonella that can lurk in raw eggs.  However, manufacturers of commercial cookie dough use pasteurized eggs in their mixes.  The scientists at the CDC instead suspect that the E. coli infection originated in a contaminated batch of flour.  Unfortunately, they were not able to confirm this hypothesis. Although 94% of the patients who became ill with E. coli O157:H7 over a few weeks in 2009 reported having eaten raw cookie dough, testing revealed very few product samples contaminated with the bacteria. It’s not clear how the cookie dough became contaminated, if in fact it was the dough that was at fault.

Still, the doctors at the CDC recommend that people not consume raw cookie dough, especially of the prepackaged commercial kind.  Seeing that this advice is unlikely to find much compliance (some of the patients admitted that they had had no intention of baking cookies when they bought the raw dough), doctors are asking manufacturers to make their product safe for raw consumption.  Some companies have responded by switching to heat-treated flour. 


Glob of raw cookie dough, by Ginny, July 25, 2008.