Investigation Details
Posted July 13, 2023
This outbreak is over. But any raw cookie dough made with unpasteurized eggs or raw flour can have germs like Salmonella and E. coli. Always follow cookie dough baking instructions in the recipe or on the package label.
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Salmonella Enteritidis infections.
Epidemiologic and traceback data showed that Papa Murphy’s raw cookie dough made people sick.
As of July 13, this outbreak is over.
Epidemiologic and Traceback Data
A total of 26 people infected with the outbreak strain of Salmonella were reported from 6 states (see map). Illnesses started on dates ranging from February 24, 2023, to May 28, 2023 (see timeline). Of 23 people with information available, 4 were hospitalized. No deaths were reported.
The true number of sick people in this outbreak was likely much higher than the number reported, and the outbreak may not have been limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella.
Public health officials collected many different types of information from sick people, including their age, race, ethnicity, other demographics, and the foods they ate in the week before they got sick. This information provided clues to help investigators identify the source of the outbreak.
The table below has information about sick people in this outbreak (“n” is the number of people with information available for each demographic).
| Demographics | Information |
|---|---|
| Age (n=26) |
Range from 14 to 81 years Median age of 48 years |
| Sex (n=26) |
81% female 19% male |
| Race (n=23) |
100% White |
| Ethnicity (n=20) |
100% non-Hispanic |
State and local public health officials interviewed people about the foods they ate in the week before they got sick. Of the 22 people interviewed, 17 reported eating food from Papa Murphy’s. Fifteen people ate Papa Murphy’s raw chocolate chip cookie dough or raw S’mores bars dough, and one person ate baked cookies made with Papa Murphy’s chocolate chip cookie dough.
Laboratory Data
Public health investigators used the PulseNet system to identify illnesses that were part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS).
WGS showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak got sick from the same food.
WGS analysis of bacteria from 26 people’s samples did not predict resistance to any antibiotics. Standard antibiotic susceptibility testing of one person’s sample by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also showed no resistance.
Public Health Actions
On May 23, Papa Murphy’s temporarily stopped selling their raw chocolate chip cookie dough and raw S’mores bars dough in response to this outbreak. As of July 13, Papa Murphy’s has not restarted sales of cookie dough and is reviewing their dessert labels to make it clear to customers that their products are not intended to be eaten raw.
CDC always advises people not to eat raw cookie dough, unless it has a label indicating that it is safe to be eaten raw.
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are collecting different types of data to investigate a multistate outbreak of Salmonella Enteritidis infections.
Epidemiologic data show that Papa Murphy’s raw cookie dough may be contaminated with Salmonella and may be making people sick.
Epidemiologic Data
As of May 23, 2023, 18 people infected with the outbreak strain of Salmonella have been reported from 6 states (see map). Illnesses started on dates ranging from February 27, 2023, to May 2, 2023 (see timeline).
Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics, and the foods they ate in the week before they got sick. This information provides clues to help investigators identify the source of the outbreak.
Sick people range in age from 14 to 68 years, with a median age of 47, and 83% are female. Of 14 people with race or ethnicity information available, all reported non-Hispanic white. Of 14 people with information available, 2 have been hospitalized. No deaths have been reported.
The true number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.
State and local public health officials are interviewing people about the foods they ate in the week before they got sick. Of the 14 people interviewed, 12 reported eating food from Papa Murphy’s. Nine people ate Papa Murphy’s raw chocolate chip cookie dough or raw S’mores bars dough, and one person ate baked cookies made with Papa Murphy’s chocolate chip cookie dough.
Laboratory Data
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS).
WGS showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak got sick from the same food.
WGS analysis of bacteria from 18 people’s samples did not predict resistance to any antibiotics. Standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently underway.
Public Health Actions
Papa Murphy’s has temporarily stopped selling their raw chocolate chip cookie dough and raw S’mores bars dough. CDC is advising people to check their refrigerator and freezer for these raw doughs and to throw any away. CDC always advises people not to eat raw cookie dough, unless it has a label indicating that it is safe to be eaten raw.
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) are collecting different types of data to identify the food source of a multistate outbreak of Salmonella Infantis infections.
Epidemiologic data show that flour contaminated with Salmonella is making people sick. Investigators are working to identify specific brands of flour that may be linked to these illnesses.
Epidemiologic Data
As of March 30, 2023, 12 people infected with the outbreak strain of Salmonella have been reported from 11 states (see map). Illnesses started on dates ranging from December 6, 2022, to February 13, 2023 (see timeline).
Public health officials collect many different types of information from sick people, including their age, race, ethnicity, other demographics, and the foods they ate in the week before they got sick. This information provides clues to help investigators identify the source of the outbreak.
Sick people range in age from 12 to 81 years, with a median age of 64, and 92% are female. Of 10 people with race or ethnicity information available, 8 are White, 2 are Asian, and no one reported Hispanic ethnicity. Of 12 people with information available, 3 have been hospitalized. No deaths have been reported.
The true number of sick people in this outbreak is likely much higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because many people recover without medical care and are not tested for Salmonella. In addition, recent illnesses may not yet be reported as it usually takes 3 to 4 weeks to determine if a sick person is part of an outbreak.
State and local public health officials are interviewing people about the foods they ate in the week before they got sick. Of the 7 people interviewed, 6 (86%) reported eating raw dough or batter. Flour was the only common ingredient in the raw dough or batter people reported eating. Investigators are working to identify a specific brand of raw flour that is linked to illnesses.
Laboratory Data
Public health investigators are using the PulseNet system to identify illnesses that may be part of this outbreak. CDC PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using a method called whole genome sequencing (WGS).
WGS showed that bacteria from sick people’s samples are closely related genetically. This suggests that people in this outbreak may have gotten sick from eating the same food.
WGS analysis of bacteria from 12 people’s samples did not predict resistance to any antibiotics. Standard antibiotic susceptibility testing by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory is currently underway.
Public Health Actions
Investigators are working to identify specific brands of flour that are linked to illness. In the meantime, CDC always advises you not to eat raw cookie dough or cake batter.
