The U.S. Department of Agriculture (USDA) has released an in-depth report detailing its investigation into a major Listeria monocytogenes outbreak connected to a Boar’s Head manufacturing facility in Jarratt, Virginia. The outbreak, which occurred between May and November 2024, resulted in 61 infections across 19 states, leading to 60 hospitalizations and 10 fatalities. The comprehensive investigation revealed significant food safety violations and has prompted widespread changes in federal inspection protocols.
Listeria – A Dangerous Pathogen
Listeriosis is the infection caused by Listeria monocytogenes. Although medical advancements and public awareness have reduced the number of listeriosis cases, outbreaks continue to occur.
Listeria infections are particularly dangerous for certain vulnerable populations. Pregnant individuals, people aged 65 or older, and those with weakened immune systems are at highest risk. Symptoms can include fever, muscle aches, headache, stiff neck, confusion, loss of balance, and convulsions, sometimes preceded by gastrointestinal symptoms. Infections rarely become critical, though complications without treatment can result in death. In pregnant individuals, however, listeriosis can lead to miscarriages, stillbirths, premature delivery, or life-threatening infections in newborns.
Anyone experiencing symptoms of Listeriosis, especially those who are pregnant, should contact a healthcare provider immediately.
Outbreak Discovery and Initial Response
The Food Safety and Inspection Service (FSIS) initiated its investigation on July 12, 2024, after cases were traced to retail-sliced deli meats. The affected population had a median age of 78 years, with 31 men and 30 women among the victims. Through whole genome sequencing analysis, investigators definitively matched the outbreak strain to contaminated liverwurst samples from the Jarratt facility, designated as establishment M12612.
Upon identifying the contamination source, FSIS launched immediate intervention measures. During July 24-25, investigators conducted intensive verification testing, collecting 81 samples: 20 product samples, 40 food contact surface samples, 20 non-food contact surface samples, and one brine sample. The investigation gained urgency when the Maryland Department of Health confirmed Listeria contamination in an unopened liverwurst package on July 25, prompting FSIS to suspend inspection of the facility’s liverwurst production line.
The Scope of Product Recalls
The investigation triggered two major product recalls. Initially, on July 26, Boar’s Head recalled approximately 207,528 pounds of liverwurst and deli meat products manufactured on the same production line as the contaminated samples. The situation escalated when investigators discovered Listeria contamination on a facility pallet jack that moved between raw and ready-to-eat areas of the plant. Following confirmation of the outbreak strain through whole genome sequencing, the company dramatically expanded its recall on July 30 to encompass all products manufactured between May 10 and July 29, 2024, totaling more than 7 million pounds of ready-to-eat meat and poultry products. The scope of the contamination ultimately led Boar’s Head to announce the indefinite closure of the Jarratt facility on September 13.
Facility History and Inspection Framework
The Jarratt facility, which had operated under a federal grant of inspection since April 1984, produced various ready-to-eat deli meats and hot dogs, including hams, bologna, liverwurst, Canadian bacon, head cheese, franks, and kielbasa. The facility operated under inspection from the Virginia Department of Agriculture and Consumer Services through a Talmadge-Aiken cooperative agreement, an arrangement that allows state inspectors to perform federal inspection duties while following FSIS regulations and requirements.
Contributing Factors to the Outbreak
The FSIS investigation revealed multiple significant factors that contributed to the outbreak, particularly centered around inadequate sanitation practices. During their review of inspection documents and establishment sampling data from January 2022 to September 2024, inspectors documented numerous instances of noncompliance with sanitation standards:
- Product Residue Management – Inspectors repeatedly found meat and fat residue from previous day’s production on equipment, including packaging machinery and in ready-to-eat processing areas. These residues could provide substrates for Listeria growth and biofilm formation, making the bacteria more resistant to cleaning procedures.
- Moisture Control Issues – The facility struggled with persistent condensation problems, including cases where condensate dripped directly onto exposed products. Investigators also documented instances where fans actively blew condensation onto product areas.
- Structural Deficiencies – The facility exhibited numerous structural problems that could harbor bacteria, including cracked floors, holes, and broken flooring capable of retaining moisture. Additional maintenance issues included widespread rust, condensation accumulation, and deteriorating caulk.
Listeria Contamination Challenges
The investigation highlighted the particular challenges posed by Listeria monocytogenes in food processing environments. The bacteria can survive and multiply at temperatures as low as 34°F (1°C), making it especially problematic in refrigerated facilities. Its ability to establish itself in processing environments and form biofilms makes it particularly difficult to eliminate once established.
FSIS Regulatory Framework and Improvements
In response to the outbreak, FSIS has implemented numerous immediate improvements to its oversight procedures and announced several long-term measures to enhance food safety protection:
- Immediate Changes
- Implementation of weekly verification requirements for Listeria-related risk factors at all ready-to-eat facilities
- Enhanced monitoring of physical plant modifications, sanitation issues, and company testing results
- Updated cooperative agreements with state inspection programs to establish clearer oversight requirements
- Strengthened enforcement expectations and inspection protocols
- Long-term Measures
- Expansion of testing protocols to include broader Listeria species detection
- Prioritization of comprehensive food safety assessments at high-risk facilities
- Development of enhanced inspector training programs
- Implementation of improved follow-up protocols for identified issues
- Revision of establishment review criteria for better risk assessment
Current Oversight and Future Changes
FSIS currently oversees approximately 2,600 ready-to-eat establishments nationwide. During fiscal year 2023, the agency collected roughly 15,000 samples through its routine sampling program, with 0.187% testing positive for Listeria monocytogenes. Despite monthly sampling at the Jarratt facility—the highest frequency in the program—the contamination issue remained undetected through routine testing, highlighting the need for enhanced surveillance methods.
The agency is seeking input from its National Advisory Committee on Microbiological Criteria for Foods to guide future policy changes. This committee, which will include new members with specific Listeria expertise, will conduct a thorough examination of FSIS’s regulatory approach and provide science-based recommendations by 2026.
Public Health Impact and Industry Context
The Centers for Disease Control and Prevention ranks Listeria infection as the third leading cause of death from foodborne illness in the United States. Annual estimates indicate approximately 1,600 infections and 260 deaths from listeriosis. The bacteria’s ability to survive in cool temperatures and establish persistent environmental presence makes it particularly challenging for food processors to control.
Recent years have seen Listeria outbreaks linked to various food products beyond deli meats, including queso fresco, peaches, ice cream, leafy greens, and enoki mushrooms. FSIS maintains a zero-tolerance standard for Listeria in ready-to-eat meat and poultry products, requiring immediate action through recalls or public health alerts for any products with detectable contamination.
Comprehensive Review and Future Regulations
The agency’s forthcoming regulatory review will examine several potential new requirements for establishments:
- Mandatory additional Listeria species testing
- Regular submission of microbial data through the External Lab Results System
- Enhanced documentation of contamination prevention measures
- New routine sampling programs for food contact and non-food contact surfaces
- Strengthened requirements for preventive controls and verification testing
Corporate-Wide Investigation
The investigation extended beyond the Jarratt facility to include reviews of other FSIS-regulated establishments owned by Boar’s Head Provisions Company. Food safety assessments were conducted at facilities in Arkansas, Indiana, Michigan, and Virginia, incorporating intensified verification testing for Listeria monocytogenes and monitoring of corrective actions for any identified deficiencies.
Resource Requirements and Implementation
The implementation of these enhanced measures will require significant additional funding, as noted in the agency’s fiscal year 2025 budget request. FSIS emphasized that protecting public health through Listeria control remains a top priority, acknowledging the pathogen’s persistent threat despite ongoing mitigation efforts.
State Inspection Program Oversight
The outbreak has also led to a reassessment of the Talmadge-Aiken program, which currently operates in nine states: Alabama, Georgia, Illinois, Mississippi, North Carolina, Oklahoma, Texas, Utah, and Virginia. Three additional states—Louisiana, South Carolina, and Vermont—maintain Cross-Utilization agreements that function similarly. FSIS has updated these cooperative agreements to include more specific requirements for oversight, training, and coordination between state and federal authorities.
The investigation of the Boar’s Head outbreak has served as a catalyst for significant changes in food safety oversight, leading to both immediate improvements in inspection protocols and long-term initiatives to enhance public health protection. As FSIS works to implement these changes, the agency acknowledges that continued vigilance and evolution of food safety measures will be essential to prevent future outbreaks of this magnitude.
