Investigation Details
Posted January 30, 2024
This outbreak is over. Stay up to date on food recalls and outbreaks to avoid getting sick from eating contaminated food. Always follow these steps to enjoy safe fruits and vegetables.
CDC, public health and regulatory officials in several states, and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Listeria monocytogenes infections.
Epidemiologic and laboratory data showed that HMC Farms peaches, nectarines, and plums might be contaminated with Listeria and made people sick.
As of January 30, 2024, this outbreak is over.
Epidemiologic Data
A total of 11 people infected with the outbreak strain of Listeria were reported from seven states (see map). Sick people’s samples were collected from August 22, 2018, to August 16, 2023 (see timeline). Of 10 people with information available, all were hospitalized. One person got sick during their pregnancy and had preterm labor. One death was reported from California.
The true number of sick people in this outbreak was likely higher than the number reported, and the outbreak may not have been limited to the states with known illnesses. This is because some people recover without medical care and are not tested for Listeria.
Public health officials collected many different types of information from sick people or their family, including their age, race, ethnicity, other demographics, and the foods they ate in the month 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=11) |
Range from 30 to 82 years Median age of 69 73% are 65 years or older |
| Sex (n=11) |
64% male 36% female |
| Race (n=10) |
80% White 10% Native Hawaiian or other Pacific Islander 10% reported more than one race |
| Ethnicity (n=9) |
89% non-Hispanic 11% Hispanic |
State and local public health officials interviewed people about the foods they ate in the month before they got sick. Of the seven people interviewed, all (100%) reported eating peaches, nectarines, or plums.
CDC conducted a case-case analysis, comparing foods reported by people in this outbreak to foods reported by people who got sick with Listeria but were not part of an outbreak. The analysis showed that people in this outbreak were 18 times more likely to eat peaches, nectarines, or plums (p<0.001) than sick people not in this outbreak. This suggested that peaches, nectarines, and plums were a likely source of this outbreak.
Laboratory Data
Public health investigators used the PulseNet system to identify illnesses that might 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 were closely related genetically. This suggested that people in this outbreak got sick from the same food.
On October 23, 2023, FDA collected a sample of HMC Farms peaches for testing and found Listeria in it. On November 6, 2023, WGS showed that the Listeria in the peaches were closely related to bacteria from sick people. This means that people likely got sick from eating those peaches.
Public Health Actions
On November 17, 2023, HMC Farms recalled whole peaches, plums, and nectarines sold in stores between May 1 and November 15 in 2022 and 2023.
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 Listeria monocytogenes infections.
Epidemiologic and laboratory data show that HMC Farms peaches, nectarines, and plums may be contaminated with Listeria and are making people sick.
Epidemiologic Data
As of November 17, 11 people infected with the outbreak strain of Listeria have been reported from seven states (see map). Sick people’s samples were collected from August 22, 2018, to August 16, 2023 (see timeline). Of ten people with information available, all have been hospitalized. One person got sick during their pregnancy and had a preterm labor. One death has been reported from California.
The true number of sick people in this outbreak is likely higher than the number reported, and the outbreak may not be limited to the states with known illnesses. This is because some people recover without medical care and are not tested for Listeria. 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.
Public health officials collect many different types of information from sick people or their family, including their age, race, ethnicity, other demographics, and the foods they ate in the month before they got sick. This information provides 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=11) |
Range from 30 to 80 years Median age of 69 73% are 65 years or older |
| Sex (n=11) |
64% Male 36% Female |
| Race (n=10) |
80% White 10% Native Hawaiian or other Pacific Islander 10% reported more than one race |
| Ethnicity (n=9) |
89% non-Hispanic 11% Hispanic |
State and local public health officials are interviewing people about the foods they ate in the month before they got sick. Of the seven people interviewed, all (100%) reported eating peaches, nectarines, or plums.
CDC conducted a case-case analysis, comparing foods reported by people in this outbreak to foods reported by people who got sick with Listeria but were not part of an outbreak. The analysis showed that people in this outbreak were 18 times more likely to eat peaches, nectarines, or plums (p<0.001) than sick people not in this outbreak. This suggests that peaches, nectarines, and plums are a likely source of this outbreak.
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.
On October 23, FDA collected a sample of HMC Farms peaches for testing and found Listeria in it. On November 6, WGS showed that the Listeria in the peaches are closely related to bacteria from sick people. This means that people likely got sick from eating these peaches.
Public Health Actions
On November 17, HMC Farms recalled whole peaches, plums, and nectarines sold in stores between May 1 and November 15 in 2022 and 2023. CDC is advising people not to eat, sell, or serve recalled fruit.
