The FDA and CDC, in collaboration with state and local partners, are investigating illnesses in a multistate outbreak of Listeria monocytogenes infections linked to Lyons ReadyCare and Sysco Imperial Frozen Supplemental Shakes.

On November 25, 2024, FDA was notified about an outbreak of Listeria monocytogenes in the United States, with many ill people residing in long-term care facilities (LTCF) prior to illness onset. FDA’s traceback investigation identified that each of the LTCF who supplied invoice information for review from 2024 to present received a frozen supplemental shake of either Lyons ReadyCare or Sysco Imperial brand. As part of this investigation, FDA collected environmental samples and found the outbreak strain of Listeria.

According to CDC, this outbreak includes cases dating back to 2018, with 20 cases across 2024 and 2025, and is currently ongoing. Epidemiologic evidence in previous investigations were unable to identify a source of the outbreak. As of February 21, 2025, a total of 38 people infected with the outbreak strain of Listeria monocytogenes have been reported from 21 states. Of the 38 people for whom information is available, 37 people have been hospitalized. Eleven deaths have been reported. Of the 38 people for whom information is available, 34 (89%) reported living in long term care facilities or were hospitalized prior to becoming sick. Records reviewed from facilities indicated nutritional shakes were available to residents.

FDA has been informed that certain Lyons ReadyCare and Sysco Imperial Frozen Supplemental Shakes are being voluntarily recalled.  FDA is working with the recalling firms. FDA’s investigation is ongoing, and more information will be provided as it becomes available.

Listeria is a gram-positive, rod-shaped bacterium that is ubiquitous and can grow under either anaerobic (without oxygen) or aerobic (with oxygen) conditions. 

A.        The Prevalence of Listeria in Food and the Environment

Listeriosis is one of the most important bacterial infections worldwide that arises mainly from the consumption of contaminated food.^[1] The disease is caused by Listeria monocytogenes, which is considered an opportunistic pathogen that affects mainly those with underlying immune conditions, such as pregnant women, neonates, and elders, resulting in septicemia, meningitis, and/or meningoencephalitis. Of the six species of Listeria, only L. monocytogenes causes disease in humans. It thrives between bacteria 86-98.6^oF (30-37^oC), but Listeria can grow at temperatures as low as −0.4°C and survive in freezing conditions down to −18°C.^[2] This unique quality allows thermal characteristics to be used as a means of differentiating Listeria from other possibly-contaminating bacteria. 

Listeria monocytogenes is omnipresent in nature; it is found widely in such places as water, soil, infected animals, human and animal feces, raw and treated sewage, leafy vegetables, effluent from poultry and meat processing facilities, decaying corn and soybeans, improperly fermented silage, and raw (unpasteurized) milk.^[3]

Foodborne listeriosis is relatively rare but is a serious disease with high fatality rates (20%–30%) compared with other foodborne microbial pathogens. Severe L. monocytogenes infections are responsible for high hospitalization rates (91%) among the most common foodborne pathogens, may cause sporadic cases or large outbreaks, and can persist in food-processing environments and multiply at refrigeration temperatures, making L. monocytogenes a significant public health concern.^[4]

Ready-to-eat foods are a notable and consistent source of Listeria. For example, a research study done by the Listeria Study Group found that L. monocytogenes grew from at least one food specimen in the refrigerators of 64% of persons with a confirmed Listeria infection (79 of 123 patients), and in 11% of more than 2,000 food specimens collected in the study. Moreover, 33% of refrigerators (26 of 79) contained foods that grew the same strain with which the individual had been infected, a frequency much higher than would be expected by chance. The danger posed by the risk of Listeria in ready-to-eat meats prompted the USDA to declare the bacterium an adulterant in these kinds of meat products and, as a result, to adopt a zero-tolerance policy for the presence of this deadly pathogen. The Code of Federal Regulations includes requirements for the post-lethality control of Listeria in meat and poultry products. This regulation is referred to as “The Listeria Rule” and was enacted in 2003. The rule outlines prevention and control measures that must be taken in processing facilities to reduce the risk of contamination of ready-to-eat products.^[5]

B.        Transmission of and Infection with Listeria

Listeria typically spreads to people through contaminated food or water but can also be transmitted from mother to fetus.

Except for the transmission of mother to fetus, human-to-human transmission of Listeria is not known to occur. Infection is caused almost exclusively by the ingestion of the bacteria, most often through the consumption of contaminated food. The most widely accepted estimate of foodborne transmission is 85-95% of all Listeria cases. 

The infective dose—that is, the number of bacteria that must be ingested to cause illness—is not known but is suspected to vary based on the strain. In an otherwise healthy person, an extremely large number of Listeria bacteria must be ingested to cause illness—estimated to be somewhere between 10-100 million viable bacteria (or colony forming units “CFU”) in healthy individuals, and only 0.1-10 million CFU in people at high risk of infection. Even with such a dose, a healthy individual will suffer only a fever, diarrhea, and related gastrointestinal symptoms.

The amount of time from infection to the onset of symptoms—typically referred to as the incubation period—can vary to a significant degree.^[6]

According to the CDC, symptoms of Listeria infection can develop at any time from the same day of exposure to 70 days after eating contaminated food. According to the FDA, gastroenteritis (or non-invasive illness) has an onset time of a few hours to 3 days, while invasive illness can have an onset varying from 3 days to 3 months. According to one authoritative text:

The incubation period for invasive illness is not well established, but evidence from a few cases related to specific ingestions points to 11 to 70 days, with a mean of 31 days. In one report, two pregnant women whose only common exposure was attendance at a party developed Listeria bacteremia with the same uncommon enzyme type; incubation periods for illness were 19 and 23 days.

Adults can get listeriosis by eating food contaminated with Listeria, but babies can be born with listeriosis if their mothers eat contaminated food during pregnancy. The mode of transmission of Listeria to the fetus is either transplacental via the maternal bloodstream or ascending from a colonized genital tract. Infections during pregnancy can cause premature delivery, miscarriage, stillbirth, or serious health problems for the newborn. Pregnant women make up around 30% of all infection cases while accounting for 60% of cases involving the 10- to 40-year age group.

C.        Who is most susceptible to Listeria monocytogenes infection?

Several segments of the population are at increased risk and need to be informed so that proper precautions can be taken. The body’s defense against Listeria is called “cell-mediated immunity” because the success of defending against infection depends on our cells (as opposed to our antibodies), especially lymphocytes, otherwise known as “T-cells.” Therefore, individuals whose cell-mediated immunity is suppressed are more susceptible to the devastating effects of listeriosis, including HIV-infected individuals, who have been found to have Listeria-related mortality of 29%. The incidence of Listeria infection in HIV-positive individuals is higher than in the general population. One study found that:

The estimated incidence of listeriosis among HIV-infected patients in metropolitan Atlanta was 52 cases per 100,000 patients per year, and among patients with AIDS it was 115 cases per 100,000 patients per year, rates 65-145 times higher than those among the general population. HIV-associated cases occurred in adults who were 29-62 years of age and in postnatal infants who were 2 and 6 months of age. 

Pregnant women naturally have a depressed cell-mediated immune system. While other systemic bacterial infections may result in adverse pregnancy outcomes at comparable frequencies, L. monocytogenes have notoriety because fetal complications largely occur in the absence of overt illness in the mother, delaying medical intervention. In addition, the immune systems of fetuses and newborns are very immature and are extremely susceptible to these types of infections. 

Other adults, especially transplant recipients and lymphoma patients, are given necessary therapies with the specific intent of depressing T-cells, and these individuals become especially susceptible to Listeria as well. Other adults, especially transplant recipients and lymphoma patients, are given necessary therapies with the specific intent of depressing T-cells, and these individuals become especially susceptible to Listeria as well.

According to the FDA, CDC, and other public health organizations, individuals at increased risk for being infected and becoming seriously ill with Listeria include the following groups:

• Pregnant women: They are about 10-20 times more likely than other healthy adults to get listeriosis. About one-third of listeriosis cases happen during pregnancy. Fetuses are also highly susceptible to infection and severe complications.
• Newborns: Newborns can develop life-threatening diseases from perinatal and neonatal infections 
• Persons with weakened immune systems 
• Persons with cancer, diabetes, kidney, or gastrointestinal disease 
• Persons with HIV/AIDS: Individuals with HIV/AIDS are almost 300 times more likely to get listeriosis than people with healthy immune systems. 
• Persons who take glucocorticosteroid medications (such as cortisone) 
• Persons of advanced age: One risk assessment showed people over 60 years old were 2.6 times more likely to develop listeriosis than the general population. And in 2011, the median age of diagnosed cases in people who were not pregnant was 71 years old. 

D.        Symptoms of Listeriosis

Only a small percentage of persons who ingest Listeria fall ill or develop symptoms. For those who do develop symptoms because of their infection, the resulting illness is either mild or quite severe, in what is sometimes referred to as a “bimodal distribution of severity.”^[7] Listeria can cause two different types of disease syndromes with differing severity. Non-invasive Listeria infection causes gastroenteritis with symptoms such as diarrhea, nausea, and vomiting that resolve on their own. Healthy adults without any immunocompromising conditions typically experience this milder version of the disease. The more severe type of disease caused by Listeria monocytogenes is called listeriosis and is referred to as an invasive illness. 

On the mild end of the spectrum, listeriosis usually consists of the sudden onset of fever, chills, severe headache, vomiting, and other influenza-type symptoms. Along these same lines, the CDC notes that infected individuals may develop fever, muscle aches, and sometimes gastrointestinal symptoms such as nausea or diarrhea. When present, the diarrhea usually lasts 1-4 days (with 42 hours being average), with 12 bowel movements per day at its worst.

The more severe form of the illness occurs when the bacteria infect parts of the body that are typically sterile, such as the blood, brain, liver, and cerebral spinal fluid. The presence of the bacteria in these areas triggers the immune response and can lead to those more severe symptoms. L. monocytogenes has a specific affinity for the central nervous system (CNS), especially in cell-mediated immunodeficient individuals.^[8]

As already noted, when pregnant, women have a mildly impaired immune system that makes them susceptible to Listeria infection. If infected, the illness appears as acute fever, muscle pain, backache, and headache. The illness usually occurs in the third trimester, which is when immunity is at its lowest. Infection during pregnancy can lead to premature labor, miscarriage, infection of the newborn, or even stillbirth. Around twenty percent of such infections result in stillbirth or neonatal death. 

Newborns may present clinically with early-onset (less than 7 days) or late-onset forms of infection (7 or more days). Those with the early-onset form are often diagnosed in the first 24 hours of life with septicemia, meningitis, or respiratory distress and have a higher mortality rate. Early-onset listeriosis is most often acquired through trans-placental transmission. Late-onset neonatal listeriosis is less common and less severe than the early-onset form. Clinical symptoms may be subtle and include irritability, fever, poor feeding, and meningitis. The mode of acquisition of late onset listeriosis is poorly understood. 

E.        Complications of Listeria Infection

For those persons who suffer a Listeria infection that does not resolve on its own, the complications can be numerous and possibly severe. The most common complication is septicemia (bacterial infection in the blood), with meningitis being the second most common. Other complications can include inflammation of the brain or brain stem (encephalitis), brain abscess, inflammation of the heart-membrane (endocarditis), septic arthritis, osteomyelitis (infection in the bone), and localized infection, either internally or of the skin. 

Death is the most severe consequence of listeriosis, and it is tragically common. The CDC has estimated that L. monocytogenes is the third leading cause of death from foodborne illness, with approximately 260 of 1,600 people diagnosed dying from their infections. For example, based on 2018 FoodNet surveillance data, 96% of 126 Listeria cases ended up in the hospital, the highest hospitalization rate for pathogenic bacterial infection. This data showed a fatality rate of 21%. According to the FDA, the case-fatality rate increases substantially based on complications, possibly reaching rates of 70% in cases with listeria meningitis, 50% in septicemia cases, and over 80% for perinatal/neonatal infections. In one US study, L. monocytogenes was reportedly the cause of nearly 4% of all cases of bacterial meningitis.

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^[1]           Reda, W. W., Abdel-Moein, K., Hegazi, A., Mohamed, Y., & Abdel-Razik, K. (2016). Listeria monocytogenes: An emerging food-borne pathogen and its public health implications. The Journal of Infection in Developing Countries, 10(02), 149-154. https://doi.org/10.3855/jidc.6616

^[2]           Santos, T., Viala, D., Chambon, C., Esbelin, J., & Hébraud, M. (2019, May 24). Listeria monocytogenes Biofilm Adaptation to Different Temperatures Seen Through Shotgun Proteomics. https://www.frontiersin.org/articles/10.3389/fnut.2019.00089/full. 

^[3]           Manning, A. (2019). Microbial Food Spoilage and Food Borne Diseases. In Food microbiology and food processing (pp. 125–130). Chapter 2. ED-TECH PRESS. 

^[4]           Arslan, F., Meynet, E., Sunbul, M. et al. The clinical features, diagnosis, treatment, and prognosis of neuroinvasive listeriosis: a multinational study. Eur J Clin Microbiol Infect Dis 34,1213–1221 (2015). https://doi.org/10.1007/s10096-015-2346-5

^[5]           USDA Staff. (2014, January 1). Controlling Listeria monocytogenes in Post-lethality Exposed Ready-to-Eat Meat and Poultry Products. https://www.fsis.usda.gov/wps/portal/fsis/topics/regulatory-compliance/guidelines/2014-0001.

^[6]           Goulet V, King LA, Vaillant V, de Valk H. What is the incubation period for listeriosis? BMC Infect Dis. 2013; 13:11. Published 2013 Jan 10. doi:10.1186/1471-2334-13-11

^[7]           Waldron, C. M. (2017, September 15). The Recovery and Transfer of Aerosolized Listeria Innocua. https://vtechworks.lib.vt.edu/handle/10919/78907. 

^[8]           Arslan, F., Meynet, E., Sunbul, M., Sipahi, O. R., Kurtaran, B., Kaya, S., … Mert, A. (2015, June). The clinical features, diagnosis, treatment, and prognosis of neuroinvasive listeriosis: a multinational study. European journal of clinical microbiology & infectious diseases: official publication of the European Society of Clinical Microbiology. https://www.ncbi.nlm.nih.gov/pubmed/25698311.

Yu Shang Food Listeria Outbreak

As of November 22, 2024, 11 people infected with the outbreak strain of Listeria have been reported from four states: California (7), Illinois (2), New York (1) and New Jersey (1). Sick people’s samples were collected from October 24, 2021, to July 31, 2024. Of 11 people with information available, nine have been hospitalized. In California, one pregnant person and their twins were sick and both infants died. Listeria was found in a sample from the mother and from one of the twin infants, but it could not be found in a sample from the other infant. One other Listeria illness was reported in an infant who was sick and recovered. On November 9, 2024, Yu Shang Food, Inc recalled ready-to-eat meat and poultry products. On November 21, 2024, Yu Shang Food, Inc expanded their recall. CDC is advising people not to eat, sell, or serve recalled products.

Boar’s Head Listeria Outbreak

As of November 19, a total of 61 people infected with the outbreak strain of Listeria were reported from 19 states: Arizona 1, Florida 3, Georgia 2, Illinois 1, Indiana 1, Louisiana 1, Massachusetts 3, Maryland 8, Minnesota 1, Missouri 3, North Carolina 1, New Jersey 6, New Mexico 1, New York 19, Pennsylvania 2, South Carolina 2, Tennessee 1, Virginia 4 and Wisconsin 1. Sick people’s samples were collected from May 29, 2024, to September 13, 2024. Of 61 people with information available, 60 were hospitalized. One person got sick during their pregnancy and remained pregnant after recovering. Ten deaths were reported, including one in Illinois, one in New Jersey, two in New York, one in Virginia, one in Florida, one in Tennessee, one in New Mexico, and two in South Carolina. Epidemiologic, laboratory, and traceback data showed that meats sliced at deli counters, including Boar’s Head brand liverwurst, were contaminated with Listeria and made people sick.

Yu Shang Food, Inc., a Spartanburg, SC, establishment, is recalling approximately 72,240 pounds of ready-to-eat (RTE) meat and poultry products within their shelf life that may be adulterated with Listeria monocytogenes, according to the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS). This release is being reissued to expand the scope of the November 9, 2024, recall.

All ready-to-eat products produced prior to October 28, 2024, are subject to recall. View full product list. View labels.

The products subject to recall bear establishment number “P-46684” or “EST. M46684” inside the USDA mark of inspection. These items were shipped to retail locations nationwide and available for purchase online.  

The problem was discovered after FSIS performed routine testing and follow-up activities of finished product produced by Yu Shang Food, Inc. on October 21, 2024, that confirmed the product was positive for Listeria monocytogenes. Additional testing has confirmed that Listeria monocytogenes was detected in product and in environmental samples collected by FSIS. Whole genome sequencing is underway to determine if these samples match the outbreak strain.

Working in conjunction with public health partners, FSIS determined that there is a link between the RTE meat and poultry products from Yu Shang Food, Inc. and an illness cluster.

Consumption of food contaminated with L. monocytogenes can cause listeriosis, a serious infection that primarily affects older adults, persons with weakened immune systems, and pregnant women and their newborns. Less commonly, persons outside these risk groups are affected.

Listeriosis can cause fever, muscle aches, headache, stiff neck, confusion, loss of balance and convulsions sometimes preceded by diarrhea or other gastrointestinal symptoms. An invasive infection spreads beyond the gastrointestinal tract. In pregnant women, the infection can cause miscarriages, stillbirths, premature delivery or life-threatening infection of the newborn. In addition, serious and sometimes fatal infections in older adults and persons with weakened immune systems. Listeriosis is treated with antibiotics. Persons in the higher-risk categories who experience flu-like symptoms within two months after eating contaminated food should seek medical care and tell the health care provider about eating the contaminated food. Anyone concerned about an injury or illness should contact a healthcare provider.

FSIS is concerned that some product may be in consumers’ refrigerators/freezers. Consumers who have purchased these products are urged not to consume them. 

As of November 22, 2024, 11 people infected with the outbreak strain of Listeria have been reported from four states – California (7), Illinois (2), New York (1) and New Jersey (1).

Sick people’s samples were collected from October 24, 2021, to July 31, 2024. Of 11 people with information available, nine have been hospitalized. In California, one pregnant person and their twins were sick and both infants died. Listeria was found in a sample from the mother and from one of the twin infants, but it could not be found in a sample from the other infant. Because of this, only the mother and one twin are included as confirmed cases in this outbreak. One other Listeria illness was reported in an infant who was sick and recovered.

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 21, 2024, FSIS conducted routine testing and follow-up activities of finished product by Yu Shang Food, Inc. Testing confirmed that the product was contaminated with Listeria. WGS showed that the Listeria in the pork snout product is closely related to bacteria from sick people. This means that people likely got sick from eating foods produced by Yu Shang Food, Inc.

On November 9, 2024, Yu Shang Food, Inc recalled ready-to-eat meat and poultry products. On November 21, 2024, Yu Shang Food, Inc expanded their recall. CDC is advising people not to eat, sell, or serve recalled products.

As of August 27, a total of 57 people infected with the outbreak strain of Listeria have been reported from 18 states – Including: Arizona 1, Florida 3, Georgia 2, Illinois 1, Indiana 1, Maryland 8, Massachusetts 3, Minnesota 1, Missouri 3, New Jersey 5, New Mexico 1, New York 17, North Carolina 1, Pennsylvania 2, South Carolina 2, Tennessee 1, Virginia 4, Wisconsin, 1.

Sick people’s samples were collected from May 29, 2024 to August 16, 2024. Of 57 people with information available, all 57 have been hospitalized. One person got sick during their pregnancy and remained pregnant after recovering. Nine deaths have been reported, including one in Illinois, one in New Jersey, one in Virginia, and as of this update one in Florida, one in Tennessee, one in New Mexico, one in New York, and two in South Carolina.

Epidemiologic, laboratory, and traceback data show that meats sliced at delis, including Boar’s Head brand liverwurst, are contaminated with Listeria and are making people sick.

Products sold at the deli, especially those sliced or prepared at the deli, can be contaminated with Listeria. Listeria spreads easily among deli equipment, surfaces, hands, and food. Refrigeration does not kill Listeria, but reheating to a high enough temperature before eating will kill any germs that may be on these meats.

Boar’s Head Provisions Co., Inc., a Jarratt, Va., establishment, is expanding its July 26, 2024, recall of deli meat products that may be adulterated with Listeria monocytogenes, the U.S. Department of Agriculture’s Food Safety and Inspection Service (FSIS) announced today. The establishment is recalling approximately 7 million additional pounds of ready-to-eat meat and poultry products. Whole genome sequencing results show that a liverwurst sample collected by the Maryland Department of Health tested positive for the outbreak strain of Listeria monocytogenes.

This expansion includes 71 products produced between May 10, 2024, and July 29, 2024, under the Boar’s Head and Old Country brand names. These items include meat intended for slicing at retail delis as well as some packaged meat and poultry products sold at retail locations. These products have “sell by” dates ranging from 29-JUL-2024 through 17-OCT-24. View full product list. View labels.

The products subject to recall were distributed to retail locations nationwide and some were exported to the Cayman Islands, Dominican Republic, Mexico, and Panama. The products shipped to retailers bear establishment number “EST. 12612” or “P-12612” inside the USDA mark of inspection on the product labels.

The problem was discovered when FSIS was notified that a liverwurst sample collected by the Maryland Department of Health tested positive for L. monocytogenes. The Maryland Department of Health, in collaboration with the Baltimore City Health Department, collected an unopened liverwurst product from a retail store for testing as part of an outbreak investigation of L. monocytogenes infections. Further testing determined the product sample tested positive for the outbreak strain. Anyone concerned about illness should contact a healthcare provider. 

CDC advises people to not eat recalled deli meat products. CDC always advises people who are pregnant, aged 65 or older, or have a weakened immune system, to avoid eating deli meats or to heat them before consuming.

.As of August 8, a total of 43 people infected with the outbreak strain of Listeria have been reported from 13 states, Georgia (2), Illinois (1), Indiana (1), Massachusetts (2), Maryland (6), Minnesota (1), Missouri (2), North Carolina (1), New Jersey (2), New York (12), Pennsylvania (1), Virginia (2) and Wisconsin (1). Sick people’s samples were collected from May 29, 2024, to July 19, 2024. Of 43 people with information available, all 43 have been hospitalized. One person got sick during their pregnancy and remained pregnant after recovering. Three deaths have been reported, including one in Illinois, one in New Jersey, and, as of this update, one in Virginia. Range in ages of illnesses is from 32 to 94 years with median age of 77.

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.

The Maryland Department of Health and Baltimore City Health Department collected an unopened Boar’s Head liverwurst product from a retail store and identified Listeria monocytogenes. Additionally, the New York State Food Laboratory identified Listeria monocytogenes from a previously collected sample of unopened Boar’s Head liverwurst products collected by the New York State Department of Agriculture and Markets’ Division of Food Safety and Inspection from retail stores. WGS determined both to be the same strain as the strain making people sick in this outbreak. USDA-FSIS conducted traceback of deli meats purchased by sick people in this outbreak to identify producers of interest for further investigation.

CDC advises people to not eat recalled deli meat products. CDC also advises people who are pregnant, aged 65 or older, or have a weakened immune system to avoid eating deli meats or to heat them before consuming.

For delis that received recalled meats:

• Thoroughly clean and sanitize all food and non-food surfaces.
• Throw away any open meats and cheeses in the deli.
• USDA-FSIS is advising delis to not use any opened deli products because recalled products can cross-contaminate other deli meats and cheeses.

Boar’s Head Ready-to-Eat Liverwurst Products

• Produced between June 11, 2024 and July 17, 2024, and have a 44-day shelf-life
• “Boar’s Head Strassburger Brand Liverwurst made in Virginia”
• 3.5-pound loaves in plastic casing, or various weight packages sliced in retail delis
• Sell by dates range from July 25, 2024, to August 30, 2024

Other Boar’s Head Deli Meat Products 

Boar’s Head also recalled all deli products, including prepackaged deli products, in shelf life from this establishment. Look for “EST. 12612” or “P-12612” inside the USDA mark of inspection on the product labels.

See the recall notice for more details about all recalled products.

• Listeria is especially harmful to people who are pregnant, aged 65 or older, or have weakened immune systems. This is because Listeria is more likely to spread beyond their gut to other parts of their body, resulting in a severe condition known as invasive listeriosis.

◦ For people who are pregnant, Listeria can cause pregnancy loss, premature birth, or a life-threatening infection in their newborn.

◦ For people who are 65 years or older or who have a weakened immune system, Listeria often results in hospitalization and sometimes death.

• Symptoms usually start within 2 weeks after eating food contaminated with Listeria, but may start as early as the same day or as late as 10 weeks after.

◦ Pregnant people usually have fever, muscle aches, and tiredness.

◦ People who are not pregnant usually have fever, muscle aches, and tiredness. They may also get a headache, stiff neck, confusion, loss of balance, or seizures.

Illnesses: 34

Hospitalizations: 33

Deaths: 2 

States: 13 – Georgia (2), Illinois (1), Indiana (1), Massachusetts (2), Maryland (6), Minnesota (1), Missouri (2), North Carolina (1), New Jersey (2), New York (12), Pennsylvania (1), Virginia (2) and Wisconsin (1).

Range in age from 32 to 94 years

Median age of 74

44% female


56% male

7,200,000 pounds of Boar’s Head Meats Recalled

Epidemiologic and laboratory data now show that meats sliced at delis, including Boar’s Head brand liverwurst, are contaminated with Listeria and are making people sick. Testing identified Listeria in an unopened package of Boar’s Head liverwurst collected as part of this investigation, which resulted in a recall. Whole genome sequencing shows this is the same strain making people sick in this outbreak.

Products sold at the deli, especially those sliced or prepared at the deli, can be contaminated with Listeria. Listeria spreads easily among deli equipment, surfaces, hands, and food. Refrigeration does not kill Listeria, but reheating to a high enough temperature before eating will kill any germs that may be on these meats.

As of July 26, 2024, a total of 34 people infected with the outbreak strain of Listeria have been reported from 13 states. Sick people’s samples were collected from May 29, 2024, to July 12, 2024. Of 33 people with information available, all 33 have been hospitalized. One person got sick during their pregnancy and remained pregnant after recovering. Two deaths have been reported, 1 in Illinois and 1 in New Jersey.

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, 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.