Don’t lick that whisk — a study published Wednesday found that tasting raw products made with flour can make you dangerously ill. Karsten Moran for The New York Times
If you are already elbow-deep in holiday cake and cookie batter, you may just want to take your chances and stop reading here.
But to become wiser and safer, though indisputably annoyed, step away from that bowl and read on.
Tasting uncooked foods made with flour can make you dangerously ill, according to a study published Wednesday in The New England Journal of Medicine. The report, which recounts the detective work that led to a recall of more than 10 million pounds of flour in the summer of 2016, confirms that a type of E. coli bacteria previously discovered lurking in wet environments like hamburger meat and leafy vegetables can also thrive in arid hosts.
“We’re not trying to ruin people’s holidays but we want them to be aware of the risks,” said Samuel J. Crowe, the lead author of the study and an epidemiologist with the division of food-borne, waterborne and environmental diseases at the Centers for Disease Control and Prevention.
“The bacteria is not uniformly distributed in a two-and-a-half pound bag of flour,” he said. “A small amount could get you really sick. I’ve had E. coli and salmonella and it’s pretty darn unpleasant.”
Because of concerns over raw eggs, precautions have long existed for licking batter-laced spoons and nibbling homemade cookie dough. But the new results expand both the array of raw goods to be concerned about — even homemade playdough! — and the reasons to be vigilant. More than a quarter of the 56 patients in the 24-state outbreak were hospitalized. One patient even went into kidney failure. All of the patients, whose ages ranged from 1 to 95, recovered.
“It’s a new view of flour,” said Dr. Marguerite A. Neill, an associate professor of medicine at Brown University Medical School and an expert on food-borne illnesses, who was not involved in this study. “It would have seemed incredible that this dry, powdery substance, stored on a shelf for months, could have a live micro-organism that didn’t spoil the flour but still could make someone sick.”
Dr. Neill, herself a baker and cook, added apologetically, “It sounds like I’m being a killjoy.”
In addition to refraining from tasting uncooked flour dishes, she advised people to wash their hands in hot, soapy water after handling flour, such as after dusting a rolling pin or dredging fish fillets. As for the final product: high, sustained cooking heat will kill pathogens.
Don’t panic: the researchers’ concerns do not include commercial treats like cookie-dough ice cream and packaged refrigerated cookie dough. Ever since 2009, when a strain of E. coli from commercial cookie dough sickened 77 people, and flour was the suspected cause, ingredients are not only pasteurized but heat-treated. (This explains why those cookie dough chunks extracted from ice cream pints don’t bake up like the real thing — though people keep trying.)
Although the recall was initiated over a year ago, the broader message about uncooked flour products was not widely known. “I was shocked. I had no idea,” said Joanne Chang, founder of Boston’s Flour Bakery and Cafe, who learned the news from a reporter, as bakers for her seven branches were filling orders for 1,000 pumpkin pies. “One of the reasons I went into pastry is because you can taste as you go along. ”
Identifying the cases and the cause was a relentless undertaking that involved doctors and clinics, state health workers and investigators from the Food and Drug Administration and the C.D.C.
The symptoms patients experienced included abdominal pain, mild fever, vomiting and diarrhea, which was often bloody. Stool samples helped isolate the strain and point to a cluster. By February 2016, federal investigators started tracking the culprit.
Dr. Neill called their work “absolutely dogged.” Researchers went through tiers of inquiry, asking patients about their food-prep and eating around the time they became ill. Tasting raw baking dough was a common factor.
Early on researchers thought the tainted ingredient could have been chocolate chips.
But thank goodness scientific detection ruled those out because the bakers used different brands.
Some patients were able to retrieve the bags of flour they used; all came from the same facility in Kansas City, Mo. Some children who fell ill had come in contact with the flour by tasting homemade playdough or raw tortilla dough that they were given at a restaurant to amuse themselves.
No contamination was found at the General Mills facilitywhere products like Gold Medal flour had been milled and packaged, researchers said. Instead, they speculated, the dangerous bacteria most likely spread earlier, as manure-dropping cattle or whitetail deer roamed through wheat fields. That means, said researchers, the bacteria, identified as two strains of Shiga toxin-producing E. coli, could reappear.
Eventually, nearly 250 products containing the flour, including cake mixes, were recalled.
A spokesman for General Mills underscored the advice not to eat raw batter, saying the company cannot heat-treat flour before packaging it. Doing so “would impact its performance, such as rising properties.”