The 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.

A total of 11 people infected with the outbreak strain of Listeria were reported from seven states – California 3, Colorado 1, Florida 3, Illinois 1, Kansas 1, Michigan 1 and Ohio 1. Sick people’s samples were collected from August 22, 2018, to August 16, 2023. 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.

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.

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. 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.