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Eating Raw Cookie Dough and Salmonella Infections

Medically Reviewed by Dan Brennan, MD on November 27, 2021

Can’t wait for those cookies to bake? It’s not easy to resist the temptation to taste that raw cookie dough.

But that’s not a safe thing to do. Raw cookie dough contains uncooked flour and eggs. These have the potential to cause food poisoning and bacterial infections like salmonella.

Eggs in Raw Cookie Dough

Raw cookie dough contains raw eggs. They may be contaminated by salmonella bacteria.

Chickens can carry the bacteria and produce eggs that contain salmonella. Eggshells can also become contaminated with salmonella bacteria when they’re laid. Eggs that contain salmonella look just like normal eggs.

Flour in Raw Cookie Dough

Raw cookie dough also contains another ingredient that you may not necessarily link to food poisoning. This ingredient is flour.

Two E. coli outbreaks in the U.S. in 2016 and 2019 had a link to raw flour. More than 80 people were infected by eating or handling the flour. 

Most people don’t consider flour to be a potentially harmful food. In a survey of 1,045 flour users in the US, researchers found that 85% were unaware of any flour recalls or outbreaks. Of those who used flour in baking, 66% said they ate raw cookie dough.

The contamination of flour usually starts in the wheat fields. Bacteria from animal feces can end up on the soil or in the water.

The farm machines that harvest the crops churn the wheat and bring in the soil’s bacteria. The wheat isn’t heated during the milling process. Heating is usually the best way to kill bacteria but this also makes it less suitable for baking.

E. coli and salmonella can survive for a long time in wheat flour. Both salmonella and E.coli bacteria can live in wheat flour stored at room temperature for 1 year.

Cookie Dough and Salmonella Infection

Salmonella bacteria live in the intestines of animals and humans. Humans are infected by this bacteria through water or food that’s been contaminated. The illness is known as salmonellosis.

Salmonella causes an estimated 26,500 hospitalizations, 1.35 million infections, and 420 deaths every year in the United States.

Symptoms. You may get symptoms within 6 hours to 6 days after infection from salmonella. The symptoms can last 4 to 7 days. 

Some people with salmonella infection may have no symptoms. Others may develop some of the following:

See your doctor if you have:

  • Vomiting or diarrhea doesn’t improve after 2 days.
  • Bloody stools.
  • A fever above 102 degrees Fahrenheit (39 degrees Celsius).

Complications. Most cases of salmonella don’t require a visit to the doctor. But there can be complications, such as dehydration.

You also have a greater risk of developing reactive arthritis after a salmonella infection. This is known as Reiter’s syndrome. It causes:

  • Painful joints
  • Irritated eyes
  • Pain when you pee

You’re also at risk for bacteremia. This is when an infection enters your bloodstream and spreads to other parts of your body.

E. Coli

Most types of E. coli bacteria are harmless. They live in the intestines of animals and healthy people. But some strains can make you very sick.

Symptoms. You may start to have symptoms anywhere from 1 day to more than 1 week after your exposure to the bacteria. Symptoms and signs include:

  • Stomach cramps
  • Diarrhea, which may be severe and bloody
  • Nausea
  • Vomiting

Complications. Healthy adults typically recover from E. coli infection within a week. But there’s a higher likelihood of developing a type of kidney failure called hemolytic uremic syndrome for younger children, older adults, and people with poor immune systems.

Is Heated Flour Safe to Eat?

You may have seen cookie dough recipes where flour is microwaved or heated in the oven first. 

There’s no scientific data to show that heating flour makes it safe to eat. Bacteria act differently in low-moisture ingredients like flour. We need more research to make sure these recipes are safe for you to eat.

Safe Handling of Raw Cookie Dough

When you bake or cook with raw ingredients like flour or eggs, it’s important to handle these foods safely. Be sure to:

  • Bake your cookie dough before you eat it. 
  • Don’t eat or taste any type of raw dough. This includes dough for cookies, cakes, pizza, bread, pancakes, crafts, and more. 
  • Don’t let young children eat or play with raw dough. Some craft projects may use raw dough.
  • Don’t use raw cookie dough in homemade ice cream. Cookie dough ice cream found in stores uses cookie dough that’s been treated.
  • Keep raw flour and raw eggs away from any foods that are ready to eat. Flour can easily spread since it’s a powder. 
  • Wash your hands well after handling raw flour and eggs. Wash bowls, utensils, tools, and surfaces with warm, soapy water. 

Show Sources

SOURCES:

Centers for Disease Control and Prevention (CDC): “Salmonella and Eggs,” Salmonella Homepage,” “Salmonella Symptoms,” “Say No to Raw Dough.”

Consumer Reports: “Don't Let Holiday Baking Make You Sick.”

frontiers in Microbiology: “Salmonella and Enterohemorrhagic Escherichia coli Serogroups O45, O121, O145 in Wheat Flour: Effects of Long-Term Storage and Thermal Treatments.”

Journal of Food Protection: “Consumer Knowledge and Behaviors Regarding Food Safety Risks Associated with Wheat Flour.”

Mayo Clinic: “E. coli,” “Salmonella infection.”

Purdue University College of Agriculture: “Home kitchen heat-treated flour doesn’t protect against foodborne illnesses, Purdue food scientist says.”

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