A multistate outbreak of Listeria monocytogenes infections associated with meat and cheese from deli counters has resulted in 13 hospitalizations, one death, and one miscarriage. The U.S. Centers for Disease Control and Prevention (CDC), public health and regulatory officials in several states, the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA’s FSIS), and the U.S. Food and Drug Administration (FDA) are currently investigating the foodborne illness outbreak.

Whole genome sequencing (WGS) data shows that meat and cheese from deli counters contaminated with L. monocytogenes are making people sick. Investigators are still working to identify any specific products or delis that may be contaminated with the outbreak strain. CDC is advising vulnerable persons to not eat meat or cheese from any deli counter, unless it is reheated to an internal temperature of at least 165 °F.

Outbreak Demographics

CDC identified 16 people across six states that have been infected with the outbreak strain of L. monocytogenes. Case patients’ samples were collected during April 17, 2021—September 29, 2022. The true number of sickened individuals is likely higher than the number reported, and the outbreak may not be limited to the states with known illnesses.

Illnesses associated with the outbreak have been identified in New York, New Jersey, Massachusetts, Maryland, Illinois, and California. Case patients range in age from 38–92 years, with a median age of 74, and 62 percent are male. Of the 13 people with ethnicity information available, 11 are of Eastern European background or speak Russian. Of the 14 people with information available, 13 have been hospitalized, including one Maryland resident who died. One person fell ill during their pregnancy, resulting in a miscarriage.

State and local public health officials are interviewing patients about the foods they ate in the month before they fell ill. Of the 12 people interviewed, 11 reported eating meat or cheese from deli counters. Among seven sickened people in New York, five bought sliced deli meat or cheese from at least one location of NetCost Market. Sickened people from other states purchased deli meats or cheeses from other delis.

Investigators do not believe that NetCost Market delis are the only source of the outbreak illnesses; a contaminated food likely introduced the outbreak strain of L. monocytogenes into delis in multiple states.

Whole Genome Sequencing Data

Public health investigators are using the CDC PulseNet system to identify illnesses that may be a part of the outbreak. PulseNet manages a national database of DNA fingerprints of bacteria that cause foodborne illnesses. DNA fingerprinting is performed on bacteria using whole genome sequencing (WGS).

WGS showed that bacteria from case patients’ samples are closely related genetically, suggesting that sickened people were infected with L. monocytogenes from the same food. In 2021, health officials in New York state and New York City found the outbreak strain in several environmental and food samples:

• Environmental samples from a NetCost Market deli in Brooklyn
• Several open packages of mortadella and ham that were sliced at the same NetCost Market deli in Brooklyn
• Sliced salami that a sickened person bought from a NetCost Market deli in Staten Island.

Actions Taken

NetCost Market voluntarily closed the deli in Brooklyn temporarily after New York officials notified them about the sampling results. NetCost Market performed a deep cleaning and then reopened the deli in Brooklyn after further environmental testing did not identify L. monocytogenes.

In September 2022, the outbreak strain was found at the same Brooklyn NetCost Market deli; however, the most recent illness associated with NetCost Market exposure was in October 2021. After a deep cleaning, additional environmental testing did not identify L. monocytogenes in the deli.