Since the last update on November 22, 2024, eight new illnesses were reported from five states. These sick people were identified after food and environmental sampling found a second strain of Listeria. As of December 5, 2024, 19 people from eight states have been infected with the outbreak strains of Listeria.

Sick people’s samples were collected from October 24, 2021, to October 28, 2024.

                  •               Of 19 people with information available, 17 (89%) have been hospitalized.

                  •               Seven illnesses are related to pregnancy.

                  •               One person who was pregnant was sick and recovered.

                  •               Two unrelated infants were also sick and recovered.

                  •               In California, a mother and her 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.

                  •               In Tennessee, a mother and her infant were sick and her infant died.

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.

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.

In response to the investigation, FSIS collected additional samples of product produced at Yu Shang Foods, Inc. and from the production environment. The Listeria found in those samples was related by WGS to the bacteria from eight other sick people in the PulseNet database and is different from the strain found in the pork snout sample and the 11 illnesses already included in the outbreak. These illnesses were combined into one investigation.

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.

Outbreaks of enteric virus infections, including hepatitis A virus (HAV) and norovirus (NoV) have been linked to fresh and frozen berries in the United States and globally. While no enteric virus outbreaks associated with domestic berries have been reported in 35 yearsExternal Link Disclaimer, there have been reported outbreaks linked to imported fresh and frozen berries.

Contamination can be the result of lapses in food safety systems and prevention methods. Key factors to consider in preventing outbreaks include proper hygienic practices of field workers, management of sanitary facilities, measures to prevent cross-contamination of fruit in field and processing operations, and measures to monitor and limit viral carriage of farm and facility workers. Further investigation is needed to better understand viral persistence in the agricultural environment, the processing environment, and in berries; routes of contamination; and public health factors.

Overview of Intestinal Illness Linked to Consumed Berries

Enteric virus (HAV and NoV) outbreaks have been associated with fresh and frozen berries consumed in the United States. The most recent HAV outbreaks occurred in 2022 and 2023, in which imported berries from the same grower were identified as the vehicle. In 2023 a joint expert panel of Food and Agriculture Organizations of the United Nations and World Health Organization identified frozen berries contaminated with HAV and NoV as one of the virus-commodity pairs of “highest global public health burden” in its updated reviewExternal Link Disclaimer of foodborne viruses and relevant food commodities of highest public health concern.

Outbreaks reported since 1997 have been linked to imported fresh and frozen berries. However, hygienic practices and challenges for the control of enteric viruses in berries and other hand-harvested produce apply globally.

Observations from outbreak investigations identified potential factors and gaps in food safety programs that were likely contributing factors to the contamination of fresh and frozen berries. Consultations with industry food safety experts identified areas of focus in understanding and managing enteric virus risk in berries.

HAV is a vaccine-preventable short-term infection that does not become chronic. People usually completely recover within several weeks. However, infections may lead to more severe health problems, including liver failure, in persons who are older or immunocompromised, have chronic liver disease, or have other underlying health conditions. Although anyone is vulnerable to HAV, the aforementioned groups of people are at higher risk of becoming infected and developing symptoms such as fatigue, nausea, vomiting, abdominal pain, jaundice, dark urine, and pale stool.

NoV in the United States, according to the Centers for Disease Control and Prevention (CDC). Most common settings for norovirus outbreaks are healthcare facilities, restaurants, catered events, schools, childcare centers, and cruise ships, food can become contaminated with norovirus at the source, including the farm.

The FDA developed a FDA Employee Health Policy Tool as part of Healthy People 2030’s norovirus workgroup initiative to reduce norovirus through retail activities.

Individuals can be infected and shed enteric virus particles before or without demonstrating symptoms, highlighting the importance of consistent application of sanitary controls.

Summary of FDA’s Strategy to Prevent Future Outbreaks of Human Hepatitis A and Human Norovirus Linked to Fresh and Frozen Berries

Food safety is a collaborative effort throughout the supply chain. Growers and processors have a responsibility to deliver safe produce in line with relevant food safety requirements. The identification and communication of effective food safety practices in fresh and frozen berry operations could benefit operators throughout the global berry industry and provide insight into effective controls for other fresh and frozen produce with similar risk factors.

Using information gained from outbreak findings, historical data, consultations with food safety experts in industry and other interest holders, the FDA has established goals and strategies to help prevent future outbreaks linked to consuming fresh or frozen berries.

This prevention strategy is designed to address factors that may contribute to the contamination of berries with enteric viruses. It outlines actions for the FDA, industry, and other interest holders to ensure accurate and timely communication and consistent application of effective prevention measures across the global berry industry. Significant efforts include:

  • Promote high rates of compliance with FDA food safety requirements.
  • Encourage the berry industry to identify and ensure consistent application of processes, or a combination of processes, which describe adequate berry pre- and post-harvest sanitary practices for domestic and global berry operations, including promoting the use of root cause analysis when failures are observed in food safety systems.
  • Broaden scientific knowledge about the viability, persistence, detection, and mitigation of viruses in fresh and frozen berries, pre- and post-harvest environments, and agricultural water sources.
  • Incentivize industry and governments to embrace the use of public health prevention measures through immunization programs to promote worker health.

Further, this strategy addresses critical knowledge gaps by fostering scientific research to enhance our ability to detect and characterize enteric viruses in various sample types and link sources of contamination using advanced laboratory methods. Research also focuses on understanding the ecology of enteric viruses in berry and other fresh produce operations. All defined goals and deliverables aim to reduce future incidences of foodborne illness linked to fresh and frozen berries.

“Collaboration between regulators, the global berry industry, and other interest holders has been critical for the development of this strategy. We look forward to on-going collaboration with all interest holders to ensure the success of this strategy, and others, for the prevention of foodborne illness,” stated Conrad Choiniere, Director of the Office of Microbiological Food Safety at the FDA’s Human Food Program (HFP).

Taylor Farm’s slivered onions have been linked to an E. coli outbreak that sickened over 100, putting 1 man in an early grave. The FDA inspection report – redacted – makes an interesting read – Full Report: Taylor Farms Colorado, Inc. of Colorado Springs, Colorado FDA Inspection Report.

FDA inspectors said over a two week period after the outbreak, they found sanitation violations at Taylor Farms Colorado, Inc. These include a failure to “conduct operations under conditions and controls necessary to minimize the potential for contamination of food.”

The FDA said the inspection was prompted by the outbreak. And though the document says the claims are “inspectional observations,” the document also says the observations “do not represent a final Agency determination.”

Inspectors categorized their observations into three categories: sanitation preventive control, monitoring, and not processing food “under conditions and controls necessary to minimize the potential for contamination of food.”

”Slivered onions and other processed vegetables are RTE (Ready to Eat) and exposed to the environment from the (redacted) step to the (redacted) step,” the report said. “According to management, the (redacted)-step is not a lethal treatment that would remove the biological hazard.”

The report cites examples of hazards, including:

  • Not allowing equipment to air dry after sanitation, which is instructed by the manufacturer of the sanitizing solution;
  • Production rooms “maintained at temperatures that would support the growth of pathogenic organisms such as Listeria;”
  • Marking an internal visual inspection as “pass” when it should have been marked “fail.” 
  • Mixing of products that shouldn’t be mixed, resulting in a customer complaint that they received onions mixed in with green peppers when it should have been just onions.

“During the inspection dates 10/28/2024 to 10/31/24, I observed several food contact surfaces … with food debris present after several full rounds of the firm’s (redacted) -step sanitation process,” the report read. 

Additionally, the report said the company’s verification methods for identifying hazards, “are not designed to determine the types of pathogens present on a surface.”

And it wasn’t just the equipment sanitation practices that inspectors found faulty.

According to the report, employees “were not observed” washing their hands and putting on new gloves once they touched unclean surfaces. Instead, they reportedly sanitized their gloved hands. Management also reported it’s “common practice for employees to only use hand sanitizer stations in the production areas.”

”Production employees handling RTE produce and food contact surfaces were not observed using any of the handwashing sinks in the facility. Employees would sometimes use the hand sanitizer over their gloved hands only.”

The CDC, public health and regulatory officials in several states, the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS), and the U.S. Food and Drug Administration (FDA) investigated a multistate outbreak of Listeria monocytogenes infections. 

Epidemiologic and laboratory data showed that meat and cheese from deli counters made people sick. A single deli or food source was not identified.  (Further epidemiological study will later confirm that food obtained from a NetCost Market was consumed by our client, ultimately causing his illness and death.) 

A total of 16 people, including a client, infected with the outbreak strain of Listeria were reported from 6 states.

Sick people’s samples were collected from April 17, 2021, to September 29, 2022. The true number of sick people in this outbreak is 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, 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.

Sick people ranged in age from 38 to 92 years, with a median age of 74, and 62% were male. Of 15 people with race or ethnicity information available, 13 were White, 1 was African American/Black, 1 was Asian, and no one reported Hispanic ethnicity. Eleven people were of Eastern European background or spoke Russian.

Of 14 people with healthcare information available, 13 were hospitalized. One person got sick during their pregnancy, resulting in pregnancy loss. Additionally, one death was reported from Maryland and one later from New York.

Of the 12 people interviewed, 11 reported eating meat or cheese from deli counters. Among seven sick people in New York, five bought sliced deli meat or cheese from at least one location of NetCost Market, a grocery store chain that sells international foods. Sick people from other states purchased deli meats or cheeses from other delis.

NetCost Market delis are unlikely to be the only source of illnesses because some sick people in the outbreak did not shop at a NetCost Market. A contaminated food likely introduced the outbreak strain of Listeria into delis in multiple states.

Public health investigators used the PulseNet system to identify illnesses that were 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 suggests that people in this outbreak got sick from the same food.

In 2021, health officials in New York state and New York City found the outbreak strain of Listeria 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; and sliced salami that a sick person bought from a NetCost Market deli in Staten Island.

NetCost Market voluntarily closed the deli temporarily in Brooklyn 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 find Listeria.

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

Data showed that deli meat and cheese bought at deli counters in multiple states were the likely sources of this outbreak. Of 12 people interviewed, 11 reported eating meat or cheese from deli counters. The outbreak strain of Listeria was found in open packages of mortadella, ham, and salami sliced at the deli, as well as a deli in Brooklyn, New York.

A single deli or food source was not identified. This is because Listeria spreads easily between food and the deli environment, and it can live for a long time in deli display cases and on equipment. A contaminated food likely introduced the outbreak strain of Listeria into delis in multiple states.

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 86-98.6oF (30-37oC), 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

[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. 

CR

In a comment letter filed with the USDA today, Consumer Reports called on the agency to strengthen its proposed regulatory framework that would keep poultry contaminated with Salmonella above a certain level off the market and subject to recall. The framework is urgently needed, given the large number of poultry plants that pose a higher risk of triggering a Salmonella outbreak given the level of Salmonella detected at their facilities by the USDA’s Food Safety and Inspection Service, according to a CR analysis.

“Salmonella infections from poultry have increased steadily over the past decade and sicken hundreds of thousands of Americans every year,” said Brian Ronholm, director of food policy at Consumer Reports. “The USDA’s current performance standards to reduce Salmonella infections from poultry have failed to drive down illnesses. We strongly support the USDA’s efforts to enact an enforceable standard to keep poultry contaminated with Salmonella off the market and urge the agency to adopt a stricter rule that will more effectively protect consumers.”

The USDA’s proposed regulatory framework would declare any chicken or turkey product as adulterated if they contain any type of Salmonella at or above 10 colony forming units (CFUs)/per millimeter or gram (10 cfu/mL(g)) and if they are contaminated with Salmonella strains of particular health concern for that commodity.

For any chicken product to be considered of public health concern under the proposed standard, it would have to be at or above 10 CFU for any Salmonellaand have detectable levels of the three serotypes: Enteritidis, Typhimurium, and I, 4 [5], 12:i-. For ground turkey to be considered of public health concern, it would have to be above 10 CFU for any Salmonella and have detectable levels of the following three serotypes: Typhimurium, Hadar, and Muenchen.

In its comment letter to the USDA, CR characterized that standard as too lax and urged the USDA to adopt an enforceable product standard for these poultry products that contain any type of Salmonella at 1 cfu/mL(g) as they did for not-ready-to-eat breaded stuffed chicken products.

While Salmonella can be spread through many foods, poultry is a leading source. Chicken alone accounts for more Salmonella infections than any other food category and has been steadily increasing over the past ten years. An estimated 195,634 illnesses are caused by Salmonella contaminated chicken, costing Americans $2.8 billion per year. According to the Centers for Disease Control and Prevention, the incidence of Salmonella illnesses in people increased between 1996 and 2022, going from 14.5 illnesses per 100,000 population in 1996 to 16.3 illnesses in 2022. Typical Salmonella infection symptoms include nausea, vomiting, severe stomach cramps, diarrhea and low-grade fever.

Salmonella contamination is widespread in chicken in part because of the often crowded and filthy conditions in which they are raised. A 2022 CR investigation, for example, found almost one-third of ground chicken samples tested contained Salmonella. Of those, 91 percent were contaminated with one of the three strains that pose the biggest threat to human health: Infantis, Typhimurium, and Enteritidis.

For a detailed explanation of Consumer Reports’ comments on the USDA proposal, see CR’s comment letter.

What we do know. Outbreak posting was 12/4/2024 as an E. coli 
O157:H7 event now tied to Romaine 
Lettuce.* The FDA says that 88 are sick and that the investigation is still Active and the notes that 
Traceback
, 
Inspection
 and Sampling has been 
Initiated.

*Earlier the FDA said: The FDA and CDC, in collaboration with state and local partners are investigating illnesses in a multistate outbreak of E. coli O157:H7 infections linked to an iceberg and romaine lettuce blend served at catering events, restaurants, and a school. Based on epidemiological information collected by CDC, a total of 69 people infected with the same strain of E. coli O157 have been reported from 10 states. FDA’s traceback investigation has identified an iceberg and romaine lettuce blend from a common supplier as the source of this outbreak; however, impacted product identified to date appears to be past shelf life and no longer on the market. FDA is continuing to work with the supplier to determine if any additional product could be impacted. At this time, there does not appear to be any ongoing risk to public health and there is no recommendation for consumers to avoid iceberg or romaine lettuce. FDA’s investigation is ongoing, and more information will be provided as it becomes available. 

A new Listeria monocytogenes outbreak from an unknown source has been detected by the Food and Drug Administration.

At least 34 patients are confirmed in the outbreak, which was first posted by the FDA on Jan. 15. The agency has begun traceback but has not reported what foods are being traced. The FDA has not reported where the patients live.

The patient count for another Listeria monocytogenes outbreak has increased to 32, up one since this past week. The outbreak was first reported by the FDA on Dec. 26, 2024. 

The agency has begun traceback but has not reported what food is being traced. The agency has also begun an on-site inspection and is conducting sample testing but has not reported what location is being inspected or what kind of samples are being tested.

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 86-98.6oF (30-37oC), 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.

[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.

I keep bumping into defense lawyers that were involved in this 2007 Salmonella Outbreak – Small World.

Public health officials in OutbreakNet (the network of epidemiologists and other public health officials, facilitated by CDC, who investigate outbreaks of foodborne, waterborne, and other enteric illnesses nationwide) are investigating a multi-state outbreak of Salmonella Wandsworth infections. Salmonella Wandsworth is a rare strain of Salmonella.

Interviews comparing foods eaten by ill and well persons show that consumption of Robert’s American Gourmet brand Veggie Booty was statistically associated with illness and therefore the most likely source of the outbreak.

As of July 18 at 11AM ET, 65 persons infected with Salmonella Wandsworth have been reported to CDC from 20 states: California, Colorado, Connecticut, Georgia, Illinois, Indiana, Massachusetts, Maryland, Minnesota, New Hampshire, New Jersey, New York, Oregon, Pennsylvania, Tennessee, Texas, Vermont, Virginia, Washington, and Wisconsin. Among the patients for whom clinical information is available, all had diarrhea, 76% had bloody stools, and six patients were hospitalized. No deaths have been attributed to these infections. Onset dates, which are known for 64 patients, ranged from February 26, 2007 to June 27, 2007. Most (91%) of cases have occurred in children aged 10 months to 3 years. During the initial phase of the outbreak, the number of cases gradually increased, with only 8 cases reported to PulseNet (the nationwide network of public health laboratories that sub-type bacteria) from 6 states before May 1, 2007. Health department and CDC investigators worked for weeks conducting interviews with parents of ill children to develop theories about possible sources of infection.

A multi-state case-control study demonstrated a strong association between illness and consumption of Veggie Booty, a snack of puffed rice and corn with a vegetable coating. CDC OutbreakNet staff shared this information with colleagues at the Food and Drug Administration (FDA) on June 27. After being informed about the outbreak by FDA, the company that manufactures the product issued a voluntary recall on June 28. None of the 65 known illnesses from Salmonella Wandsworth began after the product was recalled. Persons are advised to discard any product in their possession.

OutbreakNet officials at CDC and in state and local health departments, FDA, and the marketing and manufacturing companies are working collaboratively to learn more about production of Veggie Booty to determine how it may have become contaminated. The Minnesota Department of Agriculture Laboratory (MDAL) has isolated the outbreak strain of Salmonella Wandsworth from sealed bags of Veggie Booty obtained from retail stores. The outbreak strain has also been isolated from sealed bags of Veggie Booty by the FDA laboratory and the New York State Department of Health Wadsworth Center Laboratory. Preliminary testing suggests that the seasoning mix used in Veggie Booty may be the source of the contamination.

MDAL also isolated Salmonella Typhimurium, a different strain of Salmonella, from a sealed bag of Veggie Booty collected at the same time as the bags positive for Salmonella Wandsworth. PulseNet identified 10 persons who had illness caused by this strain of Salmonella Typhimurium between June 1, 2007 and June 27, 2007. OutbreakNet officials have interviewed 8 of the 10 ill persons with this strain of Salmonella Typhimurium and determined that all eight consumed Veggie Booty during the week before their illnesses began.

On July 2, the company expanded the recall to include Super Veggie Tings Crunchy Corn Sticks. This was done due to the company’s concern that Veggie Booty and Super Veggie Tings share ingredients that could be contaminated. Persons should discard any Super Veggie Tings in their possession. CDC is not aware of any human illnesses associated with the consumption of Super Veggie Tings.

Persons who think they may have become ill from eating Veggie Booty or Super Veggie Tings are advised to consult their health care provider. Infection with Salmonella is diagnosed by culture of a stool sample.

Most persons infected with Salmonella develop diarrhea, often with fever and abdominal cramps, 12 to 72 hours after infection. The illness usually lasts 4 to 7 days, and most persons recover without treatment. However, sometimes the illness is so severe that the patient needs to be hospitalized. The elderly, infants, and those with impaired immune systems are more likely to have severe illness.

Final Case Count Map

Persons infected with the outbreak strain of Salmonella Wandsworth, by state of residence, as of July 18, 2007 (n=65)

Map: Persons infected with the outbreak strain of Salmonella Wandsworth, by state of residence, as of July 18, 2007 (n=65)

Map updated July, 18, 2007

Case Counts Details:
*New York City case count- 8 cases
New York State case counts- 7 cases

And, where is the Inspector General’s Report? And, where are the Congressional Hearings?

Here is the final paragraph from the USDA/FISS Food Safety Assessment of the Boar’s Head in 2022 plant that in 2024 would sicken 61 – killing 10 with Listeria-tainted Liverwurst:

An analysis of the [below] stated NRs (non-compliances) indicates when not adequately addressed, these Findings could impact the establishment’s ability to produce safe, wholesome, and unadulterated product. After a review of the Fully Cooked-Not Shelf Stable written programs, SSOP/SPS/SOP recommendation of these NRs to be issued for the F-SA by iPP at the exit meeting. No follow up visit is necessary.

Full FSIS Food Safety Assessment.

  • 9 CFR 416.13(a), 9 CFR 416.13(c), and 9 CFR 416.16(a)-SSOP/Pre-op Record keeping and Insanitary conditions. Multiple pre-op deficiencies were observed in the RTE and Raw areas. The establishment failed to document the EIAOs findings and corrective actions that the establishment took.
  • 9 CFR 416.4(b), 9 CFR 416.2(a), 9 CFR 416.2(d), and 9 CFR 416.2(b)(2)-SPS Insanitary conditions. Numerous holes in the walls, damaged floors, loose caulking, product on floor, green mold, and rust were observed in the establishment.
  • 9 CFR 430.4(b)(3)(i)(D)-The establishment’s Environmental Monitoring Program failed to list all possible Food Contact Surfaces (FCS) utilized in the Post-Lethality (PL) RTE room.
  • An NR is being recommended for insanitary conditions throughout the facility. 
  • Major deficiencies associated with the establishment’s physical conditions were observed that could pose imminent threat to product. 
  • The EIAO’s observations from pre-operational verification on 09/28/2022, 09/29/2022, and 10/04/2022 showed that there were numerous insanitary conditions after the establishment completed their pre-op inspection, for example: on food contact product belts, plates, and conveyors of both the Raw and RTE processing rooms.
  • In the RTE room there were 5 clamps on the ceiling overhead piping, visually identified with rust on them, directly above product on line 3, a rusted bracket directly above the product zone of the tree wash area, a rust clamp directly above product in line 530, a rusted clamp directly above product in line 255, and 2 rusted clamps directly above product on line 1. The rust was thick and flaking on the clamps.
  • In the Raw areas was a rusted conduit bracket temperature box in the pickle room on the east end, 2 rusted conduit brackets on the north wall of the pickle room, 3 rusted conduit brackets on the water line in the pickle room, 3 rusted valve handles on the north end of the pickle room, and 2 rusted conduit brackets on the south end of the pickle room. A rusted clamp, a rusted valve, and a rusted water pipe on the water line were found on the southwest corner of the tavern line.
  • Beaded condensation beads (TNTC) were found on the doorway ceiling of the entrance holding cooler and condensation beads (TNTC) were found on the ceiling on the entrance door of frank packing area.
  • In the Cooler #5 room there was loose caulking (approximately 6″ by 2″ area at the ceiling area in the northeast corner. Ceiling hot water supply line had loose tape hanging downward in the northwest corner. Cooler #5 had heavily beaded condensation (more than 50 beads on a 20′ by 4″ area directly above RTE product. Another section of ceiling had loose tape (2- 2ft sections) hanging downward. The Blast cell hallway had loose caulking on the ceiling area hanging downward. There was a hole in the floor (approximately 3ft by 1.5″ area in the Blast cell hallway.
  • In the Frank packaging RTE room the, EIAOs observed a 4″ by 6″ forming plate (product contact) on the floor. Dirt, screws, and trash were observed on the floor of the production area. The overhead cooling units had three sections of heavy rust (approximately 2ft. by 6″ each) above the production area. Rust and grey flaking paint on the motor in line 255. Five holes and loose caulking on the northeast wall. The hot water line was leaking from the insulation around the pipe directly onto the floor.
  • In the RTE Packaging room there were numerous (1/4″ by 1/4″ area) holes completely through the glass board wall behind the hot water line. The cold-water line had damaged insulation with loose caulking at the exposed section (6″ by 3″ area of the line. Loose caulking hanging downward was observed on the ceiling at the front of line 1. Hot water line had areas of peeling tape. Numerous holes (1/4″ by 1/4″ area through the glass board wall north of line 1 shrink tunnel. Loose insulation tape coming off pipe 1 above shrink tunnel for line 3 creating insanitary conditions. Loose tape on grey water line above line 3. Damaged/exposed insulation around the hot water line. There was a gap in the insulation exposing the insulation around the steam line. Eleven holes (1/4″ by 1/4″ area were observed on the north wall near line 3. Heavily beaded condensation (approximately 6ft by 1ft a r e a near steam exhaust line for the shrink tunnel area. EQ4 room had damaged/broken (approximately 2ft by 4 in a r e a floor area. There were numerous (greater than 20) holes (1/4″ by 1/4″ area), loose caulking, and tape on the door in EQ4. Missing and exposed insulation (approximately 4″ by 4″ area) on the cold-water line for unit 15.
  • EQ3 room had hole in wall (approximately 2″ by 6″ area of northeast corner. Duct tape on south door. Loose plastic on door. Numerous holes (approximately 20 and 1/4″ by 1/4″ in area on the southwest wall.
  • EQ2 room had loose/peeling paint and loose caulking (approximately 2″ by 3′ area). Peeling rust (approximately 6″ by 20′ area on the wall pole.
  • Smoke house addition room had loose caulking above the outside door of smokehouse #10. Loose caulking above smokehouse #20 hot water line. 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 of Liver Wurst room. Numerous holes (more than 8 and 1/4″ by 1/4″ in a r e a 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. Breezeway to EQ1 room had hole in the floor (2ft by 6″ area). Thick black smoke and soot were observed covering the ceiling area. EQ1 had a hole (approximately 1ft by 1″ area) in the floor. Peeling paint (white and grey) on the wall in EQ1.
  • Raw Smoke house room had peeling paint on the old steam pipe at south side of old smoke house. Numerous holes and loose caulking on the raw smoke house doorway. Missing trim and holes on the south wall. Cold water line had peeling paint. Loose caulking on the ceiling above smokehouse #14. Holes and rust above smokehouse #6. Smoke house generator area room had boards, wood, and trash on the floor area (approximately 10ft by 12ft area). Holes in the wall and holes in ceiling area of the Smoke house generator area room. Heavily beaded smoke on overhead pipes near the smokehouses. Heavily beaded condensation (approximately 30ft by 10ft a r e a on the ceiling above smoke house generator area room. Loose caulking, loose plastic, and heavily beaded condensation on the ceiling of the smoke house generator area room. Holes in the wall west of smoke house #14. Smoke house #2 had loose caulking hanging downward above the smoke house.
  • Heavily beaded condensation on the ceiling area of the north entrance of holding cooler directly above product. Loose caulking above the holding cooler. Open vertical pipe near wall of the holding cooler. Loose caulking on floor and rust on south wall of the holding cooler. Heavily beaded condensation on the ceiling area over product staging areas for trees. Numerous rusted holes on west wall. New Gourmet room had wall damage and numerous holes (1/4″ by 1/4″ area on the north wall and doorway to the staging area for staging area for trees. Loose paint, holes, and loose caulking on the east wall. Heavily beaded condensation on the ceiling area near west wall. Holes (1/4″ by 1/4″ area on the ceiling area near southeast wall. Loose caulking on south wall. Broken curbing and holes (1/4″ by 1/4″ area) in the floor before maintenance storage area. Condensation was dripping from the hot water line directly onto the floor area. Exposed insulation around the piping of the CRV machine. Head Cheese room had a product contact shovel hanging from a rusty pipe and its handle was directly contacting the wall (non-product contact surface). Another product contact shovel was hanging from the water line (non-product contact surface) and directly contacting the west wall (non-product contact surface). Loose caulking and holes in the west wall. Loose caulking on wall above 2nd cycle blending area. Loose caulking above cooling unit for netting hams above line 3. Franks stuffing room had numerous holes in walls and numerous areas of loose caulking Standardization room had loose caulking on the south wall and numerous holes in the east wall. Rusted air filter to pump caulking on east door corner.
  • Stitch pump Il room had loose caulking on south wall. Numerous areas of green mold, large crack, and loose caulking on west wall.
  • Pickle room had greater than 20 holes in the upper part of the west wall. Loose caulking at the bottom of west wall near door. Peeling paint on south wall. A hole (approximately 6″ by 2″ area) in the south wall.
  • Live bugs (beetles) were observed on the floor the bathroom hallway.
  • On 9/28/22 EIAO’s observed: Beaded condensation (greater than 20 beads) above the dumper in the Netting room. Line 3A and Line 3B had a large black smear on the inside of the belts and a thick product residue build-up between the layers of belt. Product residue underneath the middle dumper in the rusted track are on floor. The metal supports of the dumper line had numerous areas of product residue. Strip belt had product residue (in five areas) on the product contact Teflon guides. The transfer belt had product residue (in three areas) on the metal bar that contacts the belt. The dumper belt had numerous areas of product residue on the Teflon rollers, metal guides, sprockets, belt supports, and product contact belt area. Bologna stick (product contact) was laying on the floor near the wall area. Numerous areas of product residue on the floor were observed. Two product contact pitch forks were hanging downward with the fork sections directly contacting the concrete wall. U.S Rejected tag# B 26 238183 was applied to the area at approximately 0541hrs and not removed until approximately 0646 hrs.
  • On 9/29/22 EIAO’s observed: Product residue was observed on the framework, inside support bar (product contact surface) between belt layers, and in the product contact belt to the dumper belt in the Netting room. Crack in the roller for the middle transfer line. Product residue on cross bar (product contact surface) of transfer line. Product residue on belt of line 3A. Product residue on the underside table for 3A. Head Cheese room had product residue on the screen, and it was also damaged. Line 6B had product residue in the tub. Product residue on cutting board and on stuffing horn. Product residue on the east column of east wall.
  • On 9/29/22 EIAO’s observed: The underside of the metal detector in the RTE packaging area had numerous sections of coating was peeling and hanging downward above the belt. The Packaging area had numerous sections of product residue on the plates of the Line 1| (6×4) machine, Line 2 X4) machine, Line 3 104) machine, and Line / X4) machine. Five of the white product contact tubs had product residue on the side edges and inside of them. They also were damaged and had white peeling plastic residue. The (b)(4) line 4 belt had numerus missing links in the belt. Product residue on frame to the dual infeed belt. EIAO’s also observed numerous areas of product residue on the floor area around the equipment of all four lines. Stainless steel table on North end of Line (63(4) machine had product residue on product contact table. The inedible metal cart had numerous sections of product residue in it. Product residue on the splitter frame. The product contact storage cart had thick product residue on the underneath sides directly above product contact parts. The product residue area was dripping directly onto the product contact machine parts below. On the Line 1 Frank RTE area, the EIAO’s observed product residue on the floor area around the machines. There w a s product residue on the incline belt to the (b)(4) Product residue on stripping arm of (x4) machine. The metal cover for the (b)(4) h a d product residue on the inside area. Conveyor belt leading to peeling room had product residue on the inside framework over the belt. There was a broken weld and product residue in-between the layers of belt to the conveyor to peeler room. Product residue on the outside frame of the conveyor leading to peeler room. On 10/4/22 EIAO’s observed: Product residue on the  food contact guide and numerous meat scraps on the floor area of the New Gourmet room. The Beachwood line #1 had product residue on the conveyor belt. Syrup table had product residue on it. Conveyor belt #2 had product residue (1″ by 4″) of the guard.
  • On 10/4/22 EIAO’s observed: Frank RTE room had product residue on the inside support bars of the incline to (bx4) Numerous chunks of franks were observed on the floor around the equipment near the wall and product residue around the drain. Two areas of product were observed on the floor around the vacuum pump. The RTE packaging area had product residue and wrapper stuck at roller area on the # ) metal detector. Product residue on the floor around the (bx4) line. Conveyor leading to the peeler room had product residue on the inside support bars. 

10 people died needlessly another 51 were hospitalized with a severe Listeria infection. Not to take anything away from Boar’s Head and its responsibility, but what about the USDA/FSIS’s responsibility to consumers?