“Say No to Raw Dough!” the CDC warns.
The potential problem is with two primary ingredients.
Raw flour can be contaminated with Escherichia coli (E. coli), and raw eggs have been a known carrier of salmonella bacteria.
Both bacteria are killed in the cooking process, but contaminated food that is not cooked or is undercooked has been known to make people ill, according to the CDC.
“When you’re making cookies, often the recipe calls for raw eggs,” Lindsay Malone, a registered dietitian with the Cleveland Clinic, said in 2016. “Whenever you consume raw eggs, you increase your risk of salmonella poisoning.” Malone added that “when there’s a risk for salmonella, you really want to be cautious and take steps to avoid it as much as possible.”
In recent years, public health experts have become vocal about raw flour, too.
The CDC reported that in 2016, more than 60 people across the United States were sickened with E. coli from raw 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.
That means no taste-testing batter or dough — not for cookies, cakes, pies or even bread and pizza crust.
In addition, the CDC said, children should not be permitted to play with dough because they can get sick simply from handling it.
The health agency sounds the alarm about eating raw cookie dough every year around this time, and the U.S. Department of Agriculture’s Food Safety and Inspection Service typically echoes the CDC.
However, not all public health experts agree that raw cookie dough is dangerous.
Brian Zikmund-Fisher, associate professor of health behavior and health education at the University of Michigan, wrote in the Conversation in 2016 that his family eats raw cookie dough “regularly.”
“To start, when most people think about health risks and cookie dough, they think about raw egg. Eggs can be contaminated with salmonella bacteria, and food safety recommendations encourage people to cook eggs until the white and yolk are firm in order to kill any bacteria,” Zikmund-Fisher wrote. “Because of this concern, when my kids and I make cookie dough, we never use regular eggs. Instead, we use eggs that have been pasteurized to kill any harmful bacteria without actually cooking the egg itself. (A great public health innovation, if you ask me!) So, I wasn’t worried about the eggs in the cookie dough.”
On raw flour, he said that contamination is “rare.”
To avoid potential infection, the CDC suggests not eating raw cookie dough or cake batter, of course, but also not making homemade ice cream or milkshakes with the uncooked ingredients. (However, according to the FDA, commercial cookie dough ice cream is typically safe because it is made with treated flour and pasteurized eggs.) The CDC also urges people to thoroughly wash their hands with warm, soapy water and to clean all work surfaces, dishes and utensils when working with raw eggs and flour.