A multistate Listeria outbreak linked to soft cheese has killed one person and hospitalized eight others, federal health officials confirmed. The outbreak — traced to requeson and soft ricotta-style cheeses produced by Clover Hill Dairy of Mechanicsville, Maryland — has been active for at least three years, with confirmed illness dates ranging from March 6, 2023, through May 2026.
On June 18, 2026, Clover Hill Dairy expanded its voluntary recall to include all of its cheese products after investigators found the Listeria outbreak strain in six samples of requeson cheese and in one environmental sample from the dairy's facility. The Maryland Department of Health has suspended the dairy's operating license.
Why This Matters
Listeria monocytogenes is among the most dangerous foodborne pathogens. While it causes illness in fewer people than Salmonella or E. coli, listeriosis — the illness it causes — kills approximately 20 percent of those it infects. Every year, the CDC estimates roughly 1,600 Americans develop listeriosis and 260 die.
What makes this outbreak especially important is who is most at risk: pregnant people, adults 65 and older, newborns, and immunocompromised individuals. For pregnant women, a Listeria infection can cause miscarriage, premature birth, or a life-threatening infection in the newborn — even when the mother's own illness appears mild.
Soft cheeses like requeson and ricotta-style products are high-risk vehicles because they are not cooked before eating and are often sold without complete pasteurization documentation, particularly at farmers markets and small retail locations.
What We Know So Far
According to the CDC's investigation update, as of June 9, 2026, nine people infected with the outbreak strain of Listeria have been reported from three states. Eight have been hospitalized. One person from Maryland has died.
Illness dates trace back to March 2023, indicating the source of contamination has been in distribution for more than three years — a pattern consistent with a manufacturing environment that harbored Listeria over an extended period. The PulseNet system, which identifies genetically linked Listeria cases across the country, connected these cases to a single outbreak strain.
The traceback began in May 2026, when two related cases from a single family in Suffolk County, New York, were reported to state agriculture officials. Testing of cheese samples from the family's retailer found Listeria in a repackaged requeson sample; whole-genome sequencing confirmed the strain matched the human cases. Investigators traced the cheese to Clover Hill Dairy, and a sealed 18-pound bucket of requeson from the manufacturer also tested positive.
The FDA's investigation warns that additional products may be impacted, and further testing is underway.
Where the Risk Is Highest
Clover Hill Dairy products were distributed from the company's retail market in Mechanicsville, Maryland; through farmers markets; and via third-party distributors in Maryland, New Jersey, New York, North Carolina, Virginia, and Washington, D.C. Products may have reached additional states.
Complicating matters: Clover Hill cheese is often relabeled before reaching consumers and may appear under brand names including Kesso, Quesos La Ricura, Izalco, De Mi Pueblo, and Rio Lindo. Consumers can identify Clover Hill Dairy as the manufacturer by the permit number 24-128 on the package.
An additional recall was issued by Nelson & Isa Lacteos, LLC of Bay Shore, New York, for one-pound plastic clamshell containers of requeson cheese sold at retail locations in New York from May 15 to May 28, 2026.
What Doctors and Experts Say
The FDA's investigation notes that Listeria monocytogenes can grow in refrigerator temperatures, making this recall different from most foodborne illness alerts. Discarding the recalled product is necessary but not sufficient — any surface, container, or other food that came into contact with the cheese in the refrigerator should be considered potentially contaminated.
According to the CDC, consumers should follow a specific five-step refrigerator cleaning protocol after removing recalled cheese, including washing shelves and drawers with hot soapy water, sanitizing with a dilute bleach solution, and cleaning door gaskets and seals.
The CDC also notes that for people 65 and older or those who have a weakened immune system, "Listeria often results in hospitalization and sometimes death." For this reason, anyone in a high-risk group who consumed any Clover Hill Dairy cheese product should contact their health care provider promptly — particularly if they develop any symptoms.
What the Evidence Shows — and What It Does Not
The epidemiological, laboratory, and traceback data all point to Clover Hill Dairy's requeson as contaminated with the outbreak strain. Whole-genome sequencing has confirmed the match between the environmental sample and human cases. The investigation remains ongoing to determine whether additional cheese varieties are implicated and whether the distribution footprint extends beyond the currently identified states.
The multi-year timeline of illness dates — from March 2023 to May 2026 — is particularly concerning from a public health standpoint. It suggests the Listeria contamination was embedded in the production environment for a prolonged period before it was detected.
Who Faces the Greatest Risk?
Listeria disproportionately affects:
- Pregnant people, for whom infection can cause miscarriage, stillbirth, premature labor, or severe illness in the newborn
- Adults 65 and older, who face the highest rates of hospitalization and death from invasive listeriosis
- People with weakened immune systems due to cancer, organ transplants, HIV, high-dose steroid use, or certain medications
- Newborns infected around the time of birth
The one confirmed death in this outbreak was from Maryland. All eight people with available hospitalization information were admitted for care — a hospitalization rate far higher than most foodborne illnesses.
Symptoms and Warning Signs to Watch For
Symptoms of Listeria infection can begin as early as the same day of exposure or as late as 10 weeks afterward — a longer incubation window than most foodborne illnesses.
Mild symptoms may include fever, muscle aches, nausea, tiredness, vomiting, and diarrhea.
In people at high risk, Listeria can cause invasive disease with additional symptoms including severe headache, stiff neck, confusion, loss of balance, and convulsions. In pregnant women, the primary symptoms are often fever, muscle aches, and fatigue — the infection may feel like a flu or mild illness while causing serious harm to the pregnancy.
Anyone who consumed recalled Clover Hill Dairy cheese and develops these symptoms should contact a health care provider immediately and mention their possible Listeria exposure.
What You Can Do Now
- Stop eating, selling, or serving any Clover Hill Dairy cheese product, including all varieties expanded in the June 18 recall.
- If you purchased requeson cheese in New York from May 15 to May 28, 2026, that product is also recalled by Nelson & Isa Lacteos, LLC.
- Check your refrigerator for the recalled products. If you cannot confirm whether a product is part of the recall, throw it away.
- Clean your refrigerator, all shelves, drawers, door gaskets, and any containers that may have touched the recalled cheese, using the CDC's five-step cleaning protocol .
- If you are pregnant, 65 or older, or immunocompromised and have recently consumed Clover Hill Dairy cheese, contact your health care provider promptly — even if you feel well.
- Monitor for symptoms for up to 10 weeks after your last consumption of a recalled product.
Cost and Access: What Patients Should Know
Consumers who purchased Clover Hill Dairy products can return them to the place of purchase for a refund. Those with questions can contact the Southern Maryland Agricultural Development Commission, acting on behalf of Clover Hill Dairy, at 240-528-8850, extension 327, Monday through Friday from 8 a.m. to 4:30 p.m. Eastern time.
For people without health insurance who develop symptoms, federally qualified health centers (FQHCs) offer care regardless of ability to pay and are available in most communities.
What Happens Next
The FDA's investigation is ongoing. Additional Clover Hill Dairy products may be found to be implicated, and further distribution chains are being traced. MedicalDaily will update this story as the investigation progresses and if additional products are added to the recall.
The Bottom Line
An active Listeria outbreak linked to soft cheese from Clover Hill Dairy has killed one person and hospitalized eight others across three states, with a contamination timeline extending back more than three years. Pregnant people, adults 65 and older, and immunocompromised individuals face the highest risk of severe illness and death. Anyone who purchased this cheese — under any of its brand names — should discard it immediately, clean their refrigerator thoroughly, and contact a doctor if they fall into a high-risk group.
References
- CDC — Listeria Outbreak Linked to Soft Cheese, June 2026
- CDC — Investigation Update: Listeria Outbreak, June 2026
- FDA — Outbreak Investigation: Listeria monocytogenes, Soft Cheese, June 2026
- AARP — Listeria Outbreak Linked to Soft Cheese Kills One, Sickens Seven
- Infectious Disease Advisor — Clover Hill Dairy Recalls All Cheese in Deadly Listeria Outbreak
