Boar’s Head Listeria Outbreak Revisited

On July 12, 2024, the U.S. Department of Agriculture’s (USDA) Food Safety and Inspection Service (FSIS) launched an investigation into a multistate outbreak of listeriosis linked to retail-sliced deli meats. The investigation was triggered when the Maryland Department of Health detected Listeria monocytogenes in a sample of liverwurst. In response, the Maryland Department of Health, in collaboration with the Baltimore City Health Department, collected additional unopened liverwurst products from a retail store for testing. Subsequent testing confirmed that these samples were also contaminated with the outbreak strain of Listeria monocytogenes, as identified through Whole Genome Sequencing (WGS).

The USDA’s traceback investigation, done in conjunction with the Centers for Disease Control and Prevention (CDC) and state public health partners, narrowed the source of the outbreak to Boar’s Head’s Jarratt, Virginia plant. Epidemiologic, laboratory, and traceback data showed that meats sliced at deli counters, including Boar’s Head brand liverwurst, were contaminated with Listeria and were responsible for making people ill. 

In response to the outbreak, Boar’s Head issued a recall for some of its deli meat products, including liverwurst, on July 26, 2024. The recall was expanded on July 30, 2024, to include an additional seven million pounds of ready-to-eat (RTE) meat and poultry products.

This expanded recall affected 71 products produced between May 10, 2024, and July 29, 2024, under Defendant’s Boar’s Head and Old Country brand names. The affected products included both deli-sliced meats and pre-packaged meat and poultry products. These products, bearing “sell by” dates ranging from July 29, 2024, through October 17, 2024, were distributed to retail locations across the U.S., with some exported to the Cayman Islands, Dominican Republic, Mexico, and Panama. The products involved in the recall were identified by the establishment number “EST. 12612” or “P-12612” inside the USDA mark of inspection on the product labels.

On July 31, 2024, FSIS suspended all production at Boar’s Head’s Jarratt, Virginia plant. By mid-September 2024, Boar’s Head announced the indefinite closure of the Jarratt facility, which had been identified as the source of the deadly outbreak, and the permanent cessation of all liverwurst production.

Impact of the Outbreak: Illnesses and Fatalities Across 19 States

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.

Systemic Failures at Boar’s Head’s Jarratt Facility

In the years leading up to the outbreak, government inspectors repeatedly observed and documented numerous alarming conditions at the Jarratt facility. In fact, as early as two years before the outbreak, inspectors warned that Boar’s Head’s Jarratt facility exhibited “major deficiencies” that posed an “imminent threat” to food safety, citing issues such as rusted equipment, condensation dripping onto floor, and green mold growing on walls.

USDA reports dating back to January 2022 flagged serious sanitation failures, including leftover meat on equipment, walls coated with “heavy meat buildup”, mold and mildew growing on handwashing stations used by employees handling RTE meat products, condensation dripping onto food, blood puddles on the floor, and insect infestations in areas where deli meats were processed. Between September 27 and October 4, 2022, inspectors documented food residue on the floor of the liverwurst room, live beetles in a hallway, and thick product buildup on equipment, among other violations. “Dirt, screws and trash were observed on the floor of the production area,” the report stated.

In total, FSIS issued 69 noncompliance reports for the Jarratt facility over the year leading up to the outbreak. In July 2024, federal inspectors found what appeared to be mold and mildew around handwashing sinks used by workers handling meats intended to be ready-to-eat. Mold was also discovered building up outside steel vats and in holding coolers between the facility’s smokehouses. In January 2024, one inspector noted the presence of a “black mold-like substance” at the “wall/concrete junction”, along with caulking around brick and metal. Some mold spots were “as large as a quarter.”

Other areas of the facility showed significant issues with water leakage and pooling. One puddle, for instance, was found to contain “a green algal growth”, and condensation was found “dripping over product being held.”

After inspectors flagged one of the leaks to the company, workers attempted to clean it up. “The employee wiped a third time, and the leaks returned within 10 seconds,” inspectors wrote after raising concerns about condensation on July 27, 2024. The condensation appeared to be blowing from nearby fans onto uncovered deli meats.

In February 2024, an inspector found “ample amounts of blood in puddles on the floor” and a “rancid smell” throughout a cooler used at the plant. Several records also flagged sightings of insects in and around deli meats, including one instance that led the agency to tag more than 980 pounds of ham in a smokehouse hallway for retention pending further investigation.

In June 2024, another inspection report raised concerns about flies entering “vats of pickle”. “Small flying gnat like insects were observed crawling on the walls and flying around the room. The rooms walls had heavy meat buildup,” the report noted. Other areas of the facility were similarly found to be infested with pests, including “ants traveling down the wall,” and sightings of a beetle and a cockroach.

Prior to the outbreak, Boar’s Head failed to install barriers separating processing lines, and pallet jacks and product racks were moved freely between all processing lines and blast coolers. This failure to implement basic sanitation controls violated industry standards and allowed for the spread of bacteria throughout the processing environment.

The USDA also found that Boar’s Head did not have a written plan to describe employee practices or the use of personal protection equipment (PPE) when transitioning between processing lines. This lack of procedural safeguards meant that employees were free to move between lines without changing PPE, violating standard food safety protocols. Furthermore, Boar’s Head employees who handled garbage, conducted maintenance, removed condensation, and cleaned debris from floors were permitted to move between lines without proper sanitation and PPE, further contributing to cross-contamination risks.

The USDA also noted that Defendant allowed condensation to accumulate on door openings and inside at least one blast cell, where it dripped directly onto products, leading to contamination.

These repeated violations, observed over several years, prompted the USDA to conclude that Defendant had a consistent and “intentional” practice of failing to maintain proper sanitary conditions during the processing, handling, and storing of its food products.

Emerging details about the facility’s condition continue to paint a troubling picture. A report made public on January 10, 2025, revealed the deplorable state of the liverwurst room at the Jarratt facility, including:

Entrance to Liver Wurst room had rust on the walls and ceiling. There was also rust and tape on the wall at the northeast corner. Loose caulking on the west wall in the Liver Wurst room. Rust on the floor of the east wall in Liver Wurst room. Loose caulking on the ceiling of the east wall. Holes and flaking paint on the east wall in Liver Wurst room. Numerous holes (more than 8 and 1/4” by 1/4” in area) on the east wall in Liver Wurst room. Loose caulking on overhead beam of the room. Product residue on the floor in Liver Wurst room. The Liver Wurst room strip tank window has rust on northeast wall.

In a separate report, also released in January 2025, USDA officials explicitly stated that “[a] notable contributing factor [to the Listeria outbreak] was the facility’s inadequate sanitation practices.”

The Risks of Listeria in Processing Environments

As is well understood within the food industry—and certainly by Defendant Boar’s Head—Listeria thrives in moist, refrigerated environments, and is a common contaminant in food production environments, particularly in ready-to-eat (RTE) meat products. 

The risks posed by Listeria in RTE meats are so significant that the USDA has designated the bacterium as an adulterant in these products, adopting a strict zero-tolerance policy for the presence of this deadly pathogen. The Code of Federal Regulations mandates specific measures for controlling Listeria in meat and poultry products, notably through the “Listeria Rule,” which was enacted in 2003. This regulation outlines the prevention and control protocols that must be implemented in processing facilities to reduce the risk of contamination in RTE products.

The unsanitary conditions at the Jarratt facility created a perfect breeding ground for Listeria, allowing it to spread and contaminate Boar’s Head liverwurst. These conditions, over time, enabled the bacterium to grow, thrive, and likely form biofilms—resistant microbial clusters that are difficult to eradicate—and ultimately contributed to the contamination that led to Plaintiff’s injuries.

Listeria is particularly concerning because it spreads easily across deli equipment, surfaces, hands, and food. While refrigeration does not kill Listeria, reheating the meat to a sufficiently high temperature can eliminate any harmful bacteria present. However, even if the bacteria is eliminated from the product through a kill step like cooking, it can be reintroduced through cross-contamination, making it a persistent risk.

Boar’s Head’s Numerous Claims of Quality and Safety

Despite being fully aware of the egregious conditions and substandard practices within its Jarratt facility, Boar’s Head continued to mislead consumers and retailers with false assurances about the quality and safety of its food products. The company made numerous public claims to build consumer trust, including:

• “Our products are of unquestionable quality, without compromise, using only the best natural ingredients and nothing else.”
•  “With Boar’s Head, you can trust each and every one of our products was prepared with the utmost care.”
• That Boar’s Head is “the brand consumers can count on for the highest quality delicatessen products in America.”
• Boar’s Head has “a passion to deliver on our promise for freshness and quality.”
•  “At Boar’s Head, we are committed to providing the highest quality delicatessen products. Nothing less.”
•  “[W]e are relentless about quality. If a product doesn’t live up to our exacting standards, it doesn’t carry the Boar’s Head name. Simple as that.” 
•  “That’s why Boar’s Head has been the deli brand you can trust for over 115 years.”
• That consumers deserved “better quality . . . than what was [otherwise] available.”
•  “Our standards for quality have never wavered.”
• We “only use the finest ingredients.”
•  “Commitments like these have made us a leader in our industry and have made Boar’s Head the brand in which consumers continue to place their trust.”
•  “Since 1905, our standards of quality have never wavered.”
•  “Our mission is to continue to be recognized as the leading provider of exceptional customer service and superior quality delicatessen products.”
•  “HIGHER STANDARDS FOR PREMIUM FOODS”

Additionally, Boar’s Head sought to bolster its image through certifications and partnerships with respected organizations, such as the American Heart Association, promoting its products as “heart healthy,” and the Feingold Association, which works to raise awareness of the impact of food additives on behavior, learning, and health.

Boar’s Head also made explicit promises to certain retailers, assuring them that its products were safe for human consumption, free of all adulterants, and produced to the highest standards of quality and wholesomeness.

Despite these claims, the company’s internal conditions and practices directly contradicted their public assertions, ultimately compromising both the safety and integrity of the products they marketed.

Listeria monocytogenes Bacteria

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.¹⁹

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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. 

Republished with permission from Bill Marler and Marler Clark. Copyright (c) Marler Clark LLP, PS. All rights reserved.

Source: https://www.marlerblog.com/case-news/boars-head-listeria-outbreak-revisited/