Anatomy of An Outbreak: Boar’s Head, Liverwurst, and Listeria monocytogenes

On August 28, 2024, the US Centers for Disease Control and Prevention (CDC) revealed that Listeria monocytogenes-contaminated deli meats were responsible for 57 illnesses in 18 states.

All 57 outbreak victims were hospitalized.

Nine people are dead.

The first reported victim in this outbreak (the “index case”) became ill on May 29, 2024. By July 19, 2024, the date on which the investigation began, the CDC was aware of 28 confirmed outbreak cases, including two deaths. That number increased to 34 cases just one week later.

Epidemiological and traceback data all pointed an accusatory finger in the direction of meats sliced at deli counters. Of the 44 people able to be interviewed, 41 (93%) reported eating deli meats. Thirty-nine of the 41 (95%) reported eating meats sliced at a deli. Of the 41 people who answered if they ate liverwurst, 25 (61%) reported deli-sliced liverwurst before getting sick, and 19 reported Boar’s Head brand.

As part of the outbreak investigation, the Maryland Department of Health and Baltimore City Health Department collected an unopened Boar’s Head liverwurst product from a retail store. Lab tests recovered and identified the outbreak strain of Listeria monocytogenes from the liverwurst sample.

On July 26, 2024, Boar’s Head Provisions Co., Inc. (based in Jarratt, VA) recalled all of its liverwurst products currently on the market, as well as several other deli products that had been manufactured on the same date as the sample of liverwurst from which the outbreak strain was recovered. The company expanded its recall four days later to include all outstanding products —approximately 7 million pounds of deli meats.

The recalled deli meats were distributed to retail locations throughout the USA and some were exported to the Cayman Islands, Dominican Republic, Mexico, and Panama.

The California Department of Public Health has posted a list of all retail outlets in the state where the recalled products were sold. These include large grocery chains, such as Albertson’s, Pavilions, Sprouts, Safeway, and Von’s, as well as numerous small chains and independent deli stores.

Elsewhere, consumers must rely on supermarket recall notices. The following is a list of supermarket chains that have posted notices on their websites. Follow the links to access the recall notices.

This list is far from comprehensive. For example, stores belonging to the Alberton’s group have not posted recall notices for Boar’s Head products.

Most of the reported outbreak victims live in the eastern half of the continental USA.

Confirmed cases have been documented in Arizona (1), Florida (3), Georgia (2), Illinois (1), Indiana (1), Maryland (8), Massachusetts (3), Minnesota (1), Missouri (3), New Jersey (5), New Mexico (1), New York (17), North Carolina (1), Pennsylvania (2), South Carolina (2), Tennessee (1), Virginia (4), and Wisconsin (1).

Both South Carolina victims died. The other seven deaths occurred in Florida, Illinois, New Jersey, New Mexico, New York, Tennessee, and Virginia.

According to the CDC, the true number of outbreak cases is likely higher than the 57 reported cases. People who suffer mild illnesses may not seek medical attention and their infections go unreported.

Since 2018, the CDC has reported on five Listeria monocytogenes outbreaks (including the current one) linked to consumption of deli meats or deli-sliced meats.

YearFoodCasesHospital-izationsDeathsStates
2018Deli Ham4412
2019Deli-sliced meats & cheeses101015
2020Deli meats121214
2022Deli meats & cheese161316
2024Meat sliced at delis5757918

The current Boar’s Head outbreak accounts for more illnesses, hospitalizations, and deaths than all four previous deli-related outbreaks combined.

As a manufacturer of meat and poultry products, Boar’s Head falls under the jurisdiction of the US Department of Agriculture’s Food Safety and Inspection Service (FSIS).

Unlike companies regulated by the US Food and Drug Administration (FDA), FSIS-regulated processors are inspected daily. In the case of Boar’s Head, the FSIS contracted with the Virginia Department of Agriculture and Consumer Services (VDACS) to perform those inspections.

In January 2014, FSIS issued a 143-page guidance document, “FSIS Compliance Guideline: Controlling Listeria monocytogenes in Post-lethality Exposed Ready-to-Eat Meat and Poultry Products.” The document was intended to assist processors in navigating the requirements of the agency’s Listeria rule.

In this document, the FSIS warns that, “Facilities maintenance personnel should be informed that Listeria thrives in moisture and that it is important that they vigilantly look for leaking roofs, drips, standing water, and condensation.”

Between August 1, 2023, and August 2, 2024, the VDACS inspector recorded a total of 69 instances of non-compliance, including multiple cleaning and sanitation issues, maintenance and repair issues, clogged drains, incomplete documentation, accumulation of black mold, live and dead insects, thick coatings of dust, multiple instances of condensation, leaking hot water pipe, and green algal growth in standing water.

During that same time period, the VDACS inspector submitted just twelve samples to the FSIS laboratory for analysis, none of which were positive for Listeria monocytogenes. It is unclear whether these were finished product or environmental samples.

Production has been shut down at the Jarratt facility until the source of the contamination can be identified and corrected.

The following statement appears on the Boar’s Head website:

We deeply regret the impact this recall has had on affected families. No words can fully express our sympathies and the sincere and deep hurt we feel for those who have suffered losses or endured illness.

We are conducting an extensive investigation, working closely with the USDA and government regulatory agencies, as well as with the industry’s leading food safety experts, to determine how our liverwurst produced at our Jarratt, Virginia facility was adulterated and to prevent it from happening again.

Production has been paused at our Jarratt, Virginia facility since we initiated the expanded recall in late July. We will not resume operations at this facility until we are confident that it meets USDA regulatory standards and Boar’s Head’s highest quality and safety standards.

Since last week’s release of the most recent data, multiple players have called for a congressional investigation into the actions of the company and the FSIS. Senator Blumenthal is among those who have called for a federal probe.

“The outbreak of listeria in Boar’s Head meat products should have been caught, could have been stopped by the United States Department of Agriculture,” Blumenthal was quoted by 12News Connecticut as saying. “I want an investigation as to why those lax inspection procedures caused these deaths and sicknesses.”


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FDA names second cucumber grower in US Salmonella outbreak

Thomas Produce Company (Boca Raton, FL) is a likely source of illnesses in a Salmonella outbreak that has sickened 449 individuals in 31 states and the District of Columbia, and has sent 125 people to hospital, according to an investigation update released today (August 14, 2024) by the US Food and Drug Administration.

Thomas is the second cucumber grower implicated in this outbreak. Earlier epidemiological and traceback investigations conducted by the FDA and the US Centers for Disease Control and Prevention (CDC) identified Bedner Growers, Inc. (Boynton Beach, FL) as a likely source of contaminated cucumbers.

The growing and harvesting season is over in this region, and none of the implicated cucumbers remain on the market.

No new illnesses have been reported to the CDC in recent weeks. The last illness onset date was June 4, 2024.

In an on-site inspection of Thomas Produce, the FDA recovered the outbreak strain of Salmonella Braenderup in samples of canal water used for irrigation. Multiple strains of Salmonella not linked to this outbreak also were found in soil and water samples collected at both Bedner Growers and Thomas Produce.

Salmonella strains recovered at Bedner Growers matched clinical isolates from illnesses reported in previous years.

Cucumbers supplied by these two growers do not account for all of the reported illnesses. The FDA is continuing its traceback investigations in an effort to identify additional sources of contaminated cucumbers.

Follow these four food safety steps to prevent getting sick from Salmonella.

  • Clean: Wash your hands, utensils, and surfaces often. Rinse fruits and vegetables under running water before eating, cutting, or peeling.
  • Separate: Keep food that won’t be cooked separate from raw meat, poultry, and seafood.
  • Cook: Use a food thermometer to make sure you have cooked your food to a temperature high enough to kill germs.
  • Chill: Refrigerate perishable food (food that goes bad) within 2 hours. If the outside temperature is hotter than 90°F, refrigerate within 1 hour. Thaw food in the refrigerator, not on the counter.

Call your healthcare provider if you have any of these severe Salmonella symptoms:

  • Diarrhea and a fever higher than 102°F
  • Diarrhea for more than 3 days that is not improving
  • Bloody diarrhea
  • So much vomiting that you cannot keep liquids down
  • Signs of dehydration, such as:
    • Not peeing much
    • Dry mouth and throat
    • Feeling dizzy when standing up

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Boar’s Head deli meats fingered in deadly US Listeria outbreak

A strain of Listeria monocytogenes found in a sample of Boar’s Head liverwurst is a genetic match for the outbreak strain responsible for two deaths, 33 hospitalizations, and 34 illnesses in 13 states.

The pathogen was recovered from an unopened package of liverwurst collected and analyzed by the Maryland Department of Health as part of the outbreak investigation.

Outbreak cases have been reported in Georgia (2), Illinois (1), Indiana (1), Maryland (6), Massachusetts (2), Minnesota (1), Missouri (2), New Jersey (2), New York (12), North Carolina (1), Pennsylvania (1), Virginia (2), and Wisconsin (1).

Illinois and New Jersey have each reported one fatality.

Outbreak victims range in age from 32 to 94 years, with a median age of 74 years.

People 65 years of age or older are considered to be especially susceptible to more severe illness, as are pregnant women and individuals who have a weakened immune system.

Boar’s Head Provisions Co., Inc. has announced an expansion of its earlier recall in response to the lab finding. The company is recalling approximately 7 million additional pounds of ready-to-eat meat and poultry products.

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

The recalled products were distributed to retail locations across the United States, and some were exported to the Cayman Islands, Dominican Republic, Mexico, and Panama. 

Listeria is especially harmful if you are pregnant, are aged 65 or older, or have a weakened immune system due to certain medical conditions or treatments. Other people can be infected with Listeria, but they rarely become seriously ill.

If you are pregnant, are aged 65 or older, or have a weakened immune system:

  • Do not eat recalled deli meats. Throw them away or contact stores about returns.
  • In addition, do not eat any other deli meats you get sliced at deli counters, unless it is reheated to an internal temperature of 165°F or until steaming hot. Let it cool before you eat it.
    • Listeria can grow on foods kept in the refrigerator, but it is easily killed by heating food to a high enough temperature.
  • Clean your refrigerator, containers and surfaces that may have touched sliced deli meats.
    • This is especially important if you purchased any of the recalled deli products.
  • Call your healthcare provider right away if you have any of these symptoms:
    • People who are not pregnant usually have fever, muscle aches, and tiredness. They may also get a headache, stiff neck, confusion, loss of balance, or seizures.
    • Pregnant people usually have fever, muscle aches, and tiredness. However, Listeria can cause pregnancy loss or premature birth. It can also cause serious illness or death in newborns.

For people who are generally healthy and not at higher risk of serious infection:

  • Do not eat recalled meats. Throw them away or contact stores about returns.
  • Check your refrigerator for any recalled deli meats and throw them away or return them to the store. Listeriacan grow on foods kept in the refrigerator.
  • Clean your refrigerator, containers and surfaces that may have touched recalled meats.
  • For delis that received recalled meats:
    • Thoroughly clean and sanitize all food and non-food surfaces.
    • Throw away any open meats and cheeses in the deli.
    • USDA-FSIS is advising delis to not use any opened deli products because recalled products can cross-contaminate other deli meats and cheeses.
  • Always follow USDA-FSIS best practices for controlling Listeria contamination in deli areas.

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“Reads like a true crime novel” – Food Safety News

Interested in learning more about food safety and the history of foodborne disease outbreaks and investigations?

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Chapter 6. Birth of a Pathogen

TAINTED is available in digital format from all major on-line retailers. Press the button to go directly to your preferred digital bookstore.