How Risky Is It to Eat Raw Cookie Dough?

It may be difficult to keep your fingers out of cookie dough as you're making holiday and birthday treats throughout the year, but that's exactly what the U.S. Food and Drug Administration (FDA)¹ and the Centers for Disease Control and Prevention (CDC)² advise you do.

Baking cakes and cookies has become a tradition in some families, often centered on specific celebrations. It’s common for parents to give children small bits of cookie dough to keep them occupied, or so they may form their own cookies.

However, despite opinion pieces to the contrary,³ saying no to raw dough is likely the healthiest option. The argument that Americans routinely engage in risky behavior — motorcycles, skiing and eating at restaurants where you haven’t inspected the kitchen — as a reason for eating foods potentially contaminated with dangerous bacteria is not based in sound reasoning.

Instead, it is wise to heed warnings to avoid raw cookie dough and cake batter, as they may contain dangerous bacteria that can make you and your family sick. While you might imagine raw eggs to be the root of the problem, raw flour is another ingredient triggering foodborne illness.

Say No to Raw Dough!

Senior adviser at the FDA Center for Food Safety and Applied Nutrition, Jenny Scott, warns eating raw dough or batter from bread, cookies, pizza or tortillas could make you sick. The ingredients in raw cookie dough, such as raw flour and eggs, pose a risk as they may harbor E. coli and salmonella.

Foodborne illnesses affect 1 in 6 Americans every year, resulting in 128,000 hospitalizations and 3,000 deaths.⁴ Meat is a common culprit, but most recently romaine lettuce has been recalled and alerts sent by the CDC a few days before Thanksgiving advised discarding any you might have on hand and avoiding eating romaine lettuce until further notice.⁵

According to the CDC, lettuce grown in greenhouses or hydroponically was likely not affected⁶ as the probable source of the contamination was manure runoff from a nearby concentrated animal feeding operation (CAFO).⁷ Wheat fields contaminated with animal manure may have also been the source of an outbreak of E. coli in people eating and handling raw flour.

Flour is typically not treated to kill bacteria like E. coli before being sold at the store. The grain flour is made from may be contaminated while in the field or during other steps as the flour is being produced. Although cooking flour kills these bacteria, they are present in the raw form, which is why the CDC and the FDA warn against eating raw cookie dough.

In a four-year period from 2005 to 2009, there was a foodborne outbreak of E. coli affecting over 360 people attributed to eating raw cake mix, cookie dough and flour.⁸ A study published in Clinical Infectious Diseases⁹ analyzed the results of infections from 77 patients during this period. Researchers believed it was the first reported outbreak associated with consuming ready-to-bake commercial cookie dough. The researchers wrote:¹⁰

“Despite instructions to bake brand A cookie dough before eating, case patients consumed the product uncooked. Manufacturers should consider formulating ready-to-bake commercial prepackaged cookie dough to be as safe as a ready-to-eat product. More effective consumer education about the risks of eating unbaked cookie dough is needed.”

Flour Contains Foodborne Pathogens More Often Than Previously Believed

The prepackaged cookie dough used pasteurized eggs in an effort to reduce the risk of foodborne pathogens.¹¹ However, the flour was not pasteurized, although the technology to heat the flour high enough to kill bacteria exists.¹²

Rana Lustyan, founder of Edoughble, a ready-to-eat cookie dough company, warns gluten-free products are not any safer and are not meant to be eaten raw.¹³ Heat-treated bags of flour are not typically available at the grocery store.

Following the E. coli outbreak in 2009, Nestle began using heat-treated flour for their refrigerated cookie dough, but continued to advise against consuming raw dough or batter. A study in the New England Journal of Medicine¹⁴ evaluated an outbreak of E. coli linked to consumption of raw flour, finding the problem may be more common than previously suspected.

In fact, flour has been implicated in outbreaks of foodborne illness in the U.S. and Canada. Over a two-year period 63 cases were identified spanning 24 states in the U.S., finding the infection was significantly associated with the use of General Mills flour and with tasting the unbaked dough or batter.

The researchers wrote that in addition to E. coli, other pathogens including salmonella have been detected in raw flour and implicated in investigations of infectious outbreaks. This suggests although flour is a low moisture food, it is a potential vehicle for foodborne pathogens and a potential source of infection. 

This particular outbreak resulted in the hospitalization of more than 25 percent of the patients who presented with food poisoning. One developed hemolytic uremic syndrome — kidney damage that may lead to life-threatening kidney failure.¹⁵

Bacteria Not Evenly Distributed in Flour Bags

Although consuming raw or undercooked dough or batter has been discouraged as there is a known risk of salmonellosis from consuming raw eggs, it is now apparent raw flour may also be a vehicle for foodborne pathogens. Kristi King, a senior clinical dietitian at Texas Children's Hospital, told CBS News:¹⁶

"Raw cookie dough contains both raw agriculture and animal products, both of which can carry bacteria which may be harmful to us. If you eat raw cookie dough, it's not to say you will absolutely get sick, but you raise your risk significantly in taking that gamble.

Flour is a known culprit for carrying E. coli in which symptoms may appear three to four days after consuming the product and can result in fever, cramping, bloody diarrhea and vomiting.

Raw eggs are known for carrying salmonella and this bug tends to be more quick-acting, usually six to 48 hours after consumption, and results in cramping, fever and diarrhea. In some cases, foodborne illnesses can lead to death."

This outbreak followed a similar one in Canada where 30 people became ill after eating raw flour. It was the first time this particular strain of E. coli had caused an outbreak in Canada. The non-0157 strain of E. coli is an understudied strain as most labs have only recently started testing for it. According to a CDC spokesperson:¹⁷

“Given this [Canadian] outbreak and the one in the U.S. last year linked to flour, it’s important for people to know that raw flour can be contaminated and should be cooked or baked thoroughly before eating,”

The bacteria are not uniformly distributed throughout a bag of flour. This means you may not experience any effects in your first one or two batches of cookies, but get significantly ill from the next. Lead researcher Samuel J. Crowe from the CDC commented:¹⁸

"We're not trying to ruin people's holidays but we want them to be aware of the risks. The bacteria is not uniformly distributed in a two-and-a-half pound bag of flour. A small amount could get you really sick. I've had E. coli and salmonella and it's pretty darn unpleasant."

Eating raw eggs presents another opportunity to contract a foodborne illness. Although eggs are one of the most nutritious and economical foods, it's important to take special care as even when they appear normal, eggs can contain salmonella.¹⁹ This bacterium can make you sick when the eggs are eaten raw or lightly cooked.

Although the CDC recommends considering purchasing pasteurized eggs or egg products,²⁰ a much better option is purchasing pastured, organically raised eggs from a local farmer. Keep these refrigerated at 40 degrees Fahrenheit or colder at all times and discard any cracked or dirty eggs.

However, even with these precautions, salmonella bacteria can contaminate the inside of the eggs before the shell is even formed. Therefore, it is wise to avoid eating raw eggs no matter where they are sourced.

Factory Farmed Meats Carry a Greater Risk of Exposure

Although health agencies point the finger at unsterilized foods such as raw organic milk, or uncooked flour and eggs, the food associated with the greatest number of foodborne illnesses is factory farmed chicken.

According to the CDC,²¹ there were 5,760 reported foodborne outbreaks between 2009 and 2015, resulting in 100,939 illnesses, 5,699 hospitalizations and 145 deaths. Of these, chicken was responsible for the most outbreak-associated illnesses — 3,114 illnesses (12 percent), followed by pork and seeded vegetables, each of which was responsible for 10 percent of illnesses.

Over the years, food testing shows chicken is particularly prone to contamination with dangerous pathogens, including antibiotic-resistant bacteria. Salmonella contamination is of special concern, as data suggests multidrug-resistant Salmonella has become prevalent. Raw chicken is a notorious carrier of Salmonella, Campylobacter, Clostridium perfringens and Listeria bacteria.²²

Contaminated chicken and turkey also cause the most deaths from food poisoning.²³ Large-scale factory slaughterhouses magnify the risks, as animals from multiple CAFOs are processed in one area, allowing infection in a single animal from a single farm to contaminate very large batches of meat — and any number of processed foods into which those contaminated meats are included.

Chicken isn't the only food prone to salmonella infection. Factory farmed eggs are another high-risk food as the bacteria are often deposited in the egg before the shell is formed in the chicken's body.

Antibiotic-resistant bacteria are also found in plant foods that absorb the bacteria found in agricultural soils, typically deposited via contaminated manure and/or biosolids (toxic sewage waste frequently passed off as organic potting soil)²⁴ — and this is yet another route for harmful bacteria, including drug-resistant strains, into the food system.

Pay Close Attention to Symptoms of Food Poisoning

Symptoms of food poisoning from foodborne pathogens may differ depending upon the bacteria you ingest. Symptoms of E. coli will vary from person to person but often include severe stomach cramps, bloody diarrhea and vomiting. E. coli usually triggers symptoms within three to four days after ingesting the food infected with the bacteria.²⁵

Most people recover within a week; however, young children, the elderly and those with immune deficiencies may suffer significantly worse symptoms. Some also develop a serious kidney failure called hemolytic uremic syndrome, a condition affecting the blood and blood vessels.²⁶

As a result, blood platelets are destroyed and kidney failure ensues due to damage to the small blood vessels in the kidney. Symptoms may include diarrhea and reduced urine output. Other organs dependent on microvasculature may also suffer damage, including the brain and heart.

Symptoms of salmonella infection occur more rapidly, often in six to 48 hours after eating contaminated food.²⁷ In most cases, symptoms last four to seven days but most will recover with supportive care at home. Symptoms can include diarrhea, food and abdominal cramps.

However, some may experience diarrhea many times a day for several days, resulting in dehydration requiring hospitalization for treatment. Older adults, infants and those with a weakened immune system may experience more serious illness that may be life-threatening. You should contact your health care provider if you have:²⁸

Safe Food Handling Procedures

Any time you're cooking or baking with raw ingredients it's important to follow safe food handling practices. This reduces your risk of contracting a foodborne pathogen. No matter how tempting raw cookie dough or batter may look, in order to avoid illness it's important not to eat it. The CDC also recommends:^29,30,31 

Ditch the Cookie Dough for a Chocolate Powerhouse Treat

Sometimes what you’re looking for is a rich, sweet treat. But, since adding sugar and carbohydrates to your diet spikes your insulin and inflammatory levels and increases your risk of insulin and leptin resistance, consider these chocolate fat bomb truffles instead.

Chocolate truffles are a popular type of confectionery composed of a chocolate coating and ganache, a filling made by mixing chocolate and cream. The ingredients are mixed together and rolled into balls, which are then served as treats. ³³ Their name comes from their similar appearance to truffles, a type of mushroom prized in the culinary world for its unique aroma and flavor.³⁴

However, most chocolate truffles sold contain lots of sugar, which can wreak havoc on your health. I believe it’s far better to make your own chocolate truffles using raw, organic ingredients providing a multitude of health benefits and satisfying your sweet tooth. This chocolate and avocado truffle recipe by Jennafer Ashley of Paleohacks is a great example of a healthy, delicious and easy to prepare treat.