A recent study published by The New England Journal of Medicine has revealed unwanted findings. Although it is a low-moisture food, raw flour can be a vehicle for foodborne pathogens.
The study focused on an outbreak of a strain of bacteria called Shiga toxin–which produces Escherichia coli–which caused a recall of over ten million pounds of flour. Dozens of people across the country were sickened by the bacterium.
The ensuing investigation found that raw dough eaten or handled by some of the patients was made with flour found in subsequent tests by the FDA to have the same bacterium that was making people sick. Ten million pounds of flour were recalled, including unbleached, all-purpose, and self-rising varieties.
Some of the recalled flours had been sold to restaurants that allow children to play with dough made from the raw flour while waiting for their meals. CDC advises restaurants not to give customers raw dough.
People often understand the dangers of eating raw dough due to the presence of raw eggs and the associated risk with Salmonella. However, consumers should be aware that there are additional risks associated with the consumption of raw dough, such as particularly harmful strains of E. coli in a product like flour.
“Flour is derived from a grain that comes directly from the field and typically is not treated to kill bacteria,” says Leslie Smoot, Ph.D., a senior advisor in FDA’s Office of Food Safety and a specialist in the microbiological safety of processed foods. So if an animal heeds the call of nature in the field, bacteria from the animal waste could contaminate the grain, which is then harvested and milled into flour.
Common “kill steps” applied during food preparation and/or processing (so-called because they kill bacteria that cause infections) include boiling, baking, roasting, microwaving, and frying. But with raw dough, no kill step has been used.
And don’t make homemade cookie dough ice cream either. If that’s your favorite flavor, buy commercially made products. Manufacturers should use ingredients that include treated flour and pasteurized eggs.
Symptoms and Who Gets Sick
Common symptoms for Shiga toxin-producing E. coli are diarrhea (often bloody) and abdominal cramps, although most people recover within a week. But some illnesses last longer and can be more severe, resulting in a type of kidney failure called hemolytic uremic syndrome (HUS). HUS can occur in people of any age, but is most common in young children under 5 years, older adults, and people with weakened immune systems.
Parents of young children should be particularly aware. For instance, if your child is in day care or kindergarten, a common pastime may be art using “play” clay that is homemade from raw dough. Even if they’re not munching on the dough, they’re putting their hands in their mouth after handling the dough. Childcare facilities and preschools should discourage the practice of playing with raw dough.
Handle Foods Safely
FDA offers these tips for safe food handling to keep you and your family healthy:
- Do not eat any raw cookie dough, cake mix, batter, or any other raw dough or batter product that is supposed to be cooked or baked.
- Follow package directions for cooking products containing flour at proper temperatures and for specified times.
- Wash hands, work surfaces, and utensils thoroughly after contact with flour and raw dough products.
- Keep raw foods separate from other foods while preparing them to prevent any contamination that may be present from spreading. Be aware that flour may spread easily due to its powdery nature.
- Follow label directions to chill products containing raw dough promptly after purchase until baked.