Outbreak Investigation of Listeria monocytogenes: Prepared Pasta Meals (June–October 2025)
New Recall, Expanding Case Count, and the Ongoing Federal Response to a Deadly Listeria Outbreak
The multistate outbreak of Listeria monocytogenes linked to prepared pasta meals, first identified in June 2025, has taken a tragic turn. On October 6, 2025, the U.S. Food and Drug Administration (FDA), in coordination with the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA FSIS) and the Centers for Disease Control and Prevention (CDC), released an update confirming that 20 illnesses across 15 states have now been connected to the outbreak.
Of those infected, 19 people have been hospitalized, four have died, and one pregnancy has ended in fetal loss. The severity of outcomes underscores the danger that Listeria monocytogenes poses, especially through foods not typically associated with high risk, like refrigerated pasta dishes.
This new phase of the investigation comes after Giant Eagle’s voluntary recall on October 3, covering its “Smoked Mozzarella Pasta Salad” sold in prepared food departments at Giant Eagle and Market District locations across western Pennsylvania, Ohio, Maryland, and Indiana. The recall marks the first confirmed commercial link to this ongoing outbreak.
FDA, USDA FSIS, and CDC continue to collaborate with state and local health departments to trace supply chains and confirm contamination sources. The agencies have emphasized that their work remains active and that “updates will be provided as they become available.”
The Timeline of the Investigation
The Listeria monocytogenes outbreak tied to prepared meals first surfaced in June 2025, when state health officials in Ohio and Pennsylvania began reporting severe Listeria infections among people who had recently eaten store-bought refrigerated pasta dishes. Genetic sequencing of patient isolates revealed a shared strain, triggering a coordinated federal investigation.
Throughout summer 2025, public health agencies collected clinical and environmental samples from production facilities that manufacture or package precooked pasta meals and salads. Although the pathogen was detected in several retail products, investigators initially lacked sufficient evidence to tie contamination to a specific producer or brand.
By late September, however, the epidemiologic picture became clearer. According to the CDC’s latest summary, of the 13 patients interviewed, seven (54%) reported eating precooked meals, and four specifically mentioned chicken fettuccine alfredo purchased from grocery store deli counters.
On October 3, Giant Eagle announced a voluntary recall after internal traceability reviews and preliminary test results suggested possible contamination in its “Smoked Mozzarella Pasta Salad.” This product was sold in prepared foods departments, a category known for being at elevated risk for Listeria growth because of temperature fluctuations and extended refrigerated storage.
The FDA has not yet confirmed whether the same outbreak strain was found in the recalled product, but the timing and epidemiologic overlap indicate a strong correlation.
The Scope of the Outbreak
As of September 25, 2025, a total of 20 people have been infected across 15 states. The known geographic distribution includes:
- Ohio, Pennsylvania, Maryland, Indiana, and several others under ongoing investigation.
While the CDC continues to withhold state-level counts pending verification, public health labs have confirmed that all cases share a nearly identical whole genome sequencing (WGS) pattern (FDA.gov), a strong indicator that these infections stem from a common source.
The infection rate and outcomes place this event among the deadliest U.S. listeriosis outbreaks in recent years, rivaling the 2024 Boar’s Head deli meat outbreak and the 2022 Big Olaf Creamery ice cream incident (FDA.gov).
Understanding Listeria monocytogenes
What is Listeria?
Listeria monocytogenes is a pathogenic bacterium capable of causing a serious infection known as listeriosis. Unlike many other foodborne pathogens, Listeria can survive and grow at refrigerator temperatures, which allows it to persist in ready-to-eat (RTE) foods, especially those stored for long periods or not reheated before consumption.
Why Listeria is different
While bacteria like Salmonella or E. coli typically cause self-limiting gastrointestinal illness, Listeria poses a greater danger because it invades the bloodstream and central nervous system. It can also cross the placental barrier, leading to miscarriage, stillbirth, or severe neonatal infection.
High-risk foods
Common sources of Listeria include:
- Soft cheeses made from unpasteurized milk
- Deli meats and hot dogs
- Refrigerated pâtés and meat spreads
- Smoked seafood
- Ready-to-eat salads and pre-cooked pasta dishes
Prepared pasta meals, especially those with cream- or cheese-based sauces, create an ideal environment for Listeria growth when stored improperly or contaminated post-processing.
Why Prepared Meals Are a Growing Food Safety Concern
Prepared and ready-to-eat meals have become a cornerstone of modern convenience. Grocery chains like Giant Eagle and Market District rely on centralized kitchens and commissaries to produce salads, pastas, and hot bar items distributed to multiple retail locations.
However, this model carries inherent risks:
- Complex supply chains (NIH.gov) make it difficult to trace ingredients back to specific sources.
- Multiple handling points increase the chance of contamination.
- Cold-chain breaches during storage or transport allow Listeria to multiply.
- Cross-contamination can occur when raw and cooked ingredients share equipment or prep areas.
Even when prepared meals are refrigerated, Listeria’s ability to grow at low temperatures makes it a persistent hazard.
Why Listeria Still Evades Detection
Food safety experts emphasize that Listeria’s persistence in food facilities is what makes it so challenging to eliminate. Listeria monocytogenes can establish long-term niches in processing environments, especially in drains, floors, and equipment seams, where routine sanitation may not reach.
Additionally, Listeria doesn’t need a warm environment. It can grow at 40°F, which means your refrigerator isn’t enough to stop it. This persistence is why Listeria outbreaks linked to chilled ready-to-eat products, like salads, cheeses, or deli meats, continue to surface despite modern sanitation systems.
The repeated appearance of Listeria in refrigerated ready-to-eat products demonstrates both progress and limits in current food safety systems: genetic sequencing allows for rapid detection, but environmental persistence remains a powerful challenge.
The Giant Eagle Recall and Industry Implications
Giant Eagle’s voluntary recall of its “Smoked Mozzarella Pasta Salad” marks a major development in the investigation. The recall applies to products sold through in-store prepared food departments, not prepackaged retail units, indicating that contamination may have occurred during food preparation or cold storage rather than during manufacturing.
According to the company’s statement:
“Out of an abundance of caution, Giant Eagle has recalled all varieties of the Smoked Mozzarella Pasta Salad sold in prepared food departments. Guests are advised not to consume the product and to return it for a full refund.”
This recall not only implicates the retailer but also highlights systemic vulnerabilities in fresh food service models, where products are made or portioned on-site, often in open kitchens.
Listeria’s Impact on Vulnerable Populations
The outcomes reported in this outbreak, four deaths and one fetal loss, underscore Listeria’s predilection for the most vulnerable groups. The CDC notes that pregnant people, newborns, adults aged 65 and older, and those with weakened immune systems face the highest risk of severe illness.
For pregnant individuals, even mild flu-like symptoms may mask a potentially devastating infection. Listeria can cross the placenta, leading to miscarriage, stillbirth, premature labor, or neonatal sepsis.
For elderly and immunocompromised patients, listeriosis can escalate to meningitis, sepsis, or encephalitis, requiring prolonged hospitalization. The current outbreak’s hospitalization rate of 95% starkly illustrates this risk.
What Makes This Outbreak Different
While Listeria outbreaks in deli meats and dairy are relatively common, linking it to prepared pasta dishes, such as chicken fettuccine alfredo and smoked mozzarella salad, is unusual. According to the national food poisoning lawyer, Ron Simon, “It reflects the expanding footprint of ready-to-eat foods in grocery retail and the difficulty of ensuring safety in foods that combine cooked and raw elements.”
Moreover, the high hospitalization and fatality rates suggest that this outbreak involves a particularly virulent strain or that contaminated products reached highly susceptible consumers.
The Role of Whole Genome Sequencing (WGS)
Whole genome sequencing has transformed outbreak investigations, enabling scientists to link patient samples with food or environmental sources at an unprecedented level of precision. The current investigation’s reliance on WGS allowed CDC and FDA to connect cases across 15 states even before a single product was recalled.
Genomic sequencing is a crucial tool that helps us connect individual illness cases and reveal hidden links between contaminated foods and outbreaks that might have otherwise gone undetected. This technology not only identifies contaminated products but also helps regulators identify persistent contamination in food processing environments, potentially leading to long-term improvements in food safety.
Analysis & Next Steps
What’s new: The October 2025 FDA update confirmed 20 illnesses, 19 hospitalizations, four deaths, and one fetal loss linked to a Listeria monocytogenes outbreak associated with prepared pasta meals. The Giant Eagle recall of “Smoked Mozzarella Pasta Salad” is the first concrete product action in this months-long investigation, and more recalls could follow as testing continues.
Why it matters: This outbreak underscores how Listeria continues to find footholds in modern food systems—even in foods perceived as low-risk. Prepared meals, refrigerated pasta, and deli salads are increasingly popular, yet they combine the danger of prolonged cold storage with frequent human handling. The event exposes weaknesses in grocery prepared-food oversight and highlights the importance of strong sanitation protocols, temperature monitoring, and supplier transparency.
Who’s affected: So far, patients span 15 states, suggesting a wide distribution network. The most severely impacted populations include older adults, immunocompromised individuals, and pregnant women. Grocery shoppers who frequently purchase deli or prepared meals in refrigerated cases should remain vigilant.
What to do now:
- Consumers:
- Check refrigerators and freezers for recalled Giant Eagle “Smoked Mozzarella Pasta Salad” and discard immediately.
- Clean and sanitize refrigerator shelves and containers that may have come into contact with the product.
- Pregnant individuals, seniors, and those with compromised immunity should avoid refrigerated ready-to-eat products until further notice from FDA or CDC.
- Retailers and distributors:
- Isolate and destroy affected products.
- Conduct deep cleaning and environmental sampling in preparation and display areas.
- Review supplier documentation and temperature logs for cold storage compliance.
- Regulators and public health officials:
- Continue genomic sequencing to confirm links between food and patient isolates.
- Share real-time data with states to enable rapid recalls.
- Evaluate whether stronger oversight of grocery prepared-food departments is warranted.
Final Note
This outbreak, one of the deadliest of 2025, illustrates how Listeria monocytogenes continues to challenge the nation’s food safety systems, especially in the rapidly growing ready-to-eat sector. Despite decades of advances in detection and prevention, the pathogen’s persistence in food facilities and its ability to thrive in cold environments make it a formidable threat.
As FDA and CDC continue tracing the contamination source, consumers should remain alert to recall notices and prioritize food safety at home. Washing hands, sanitizing refrigerators, and heating ready-to-eat meals to steaming hot before eating can dramatically reduce risk.
The Listeria outbreak linked to prepared pasta meals serves as a sobering reminder: convenience foods can carry hidden hazards, and vigilance, from farm to fork, remains the strongest defense against deadly foodborne pathogens.
