Federal regulators have linked a listeriosis outbreak spanning more than three years to soft cheese produced by Clover Hill Dairy, LLC, a small plant in Mechanicsville, Maryland. Nine illnesses, eight hospitalizations, and one death have been tied to the dairy’s requeson and ricotta-style products, according to federal investigators. The company has now recalled every cheese variety it manufactures, and Maryland health officials have suspended the facility’s operating license.
Three years of Listeria cases traced to a single Maryland plant
The timeline of this outbreak is what sets it apart from routine food recalls. Case sample collection dates stretch from March 6, 2023, to May 10, 2026, according to the FDA’s outbreak investigation. That three-year window raises a pointed question: how did contaminated cheese continue reaching consumers for so long before triggering a recall?
Listeria monocytogenes is notoriously difficult to eliminate from food-processing environments. The bacterium forms biofilms on surfaces such as drains, cutting boards, and aging shelves, and it thrives at refrigerator temperatures where most other pathogens slow down. In small dairy operations that produce soft or fresh cheeses, those conditions create persistent risk. Standard cleaning may suppress but not eradicate the organism once it establishes itself in production areas. The extended illness timeline here suggests that whatever sanitation practices were in place at plant number 24-128 did not break the cycle of contamination.
According to the CDC, eight people fell sick across Maryland, New York, and Virginia, with seven hospitalizations and one death in Maryland. The FDA’s count is slightly higher, listing nine illnesses and eight hospitalizations. That discrepancy likely reflects different reporting cutoff dates rather than a disagreement between agencies, but no official explanation has been published. Health officials have not identified any additional deaths connected to the outbreak beyond the single fatality reported in Maryland.
Recall scope, license suspension, and repackaged product
Clover Hill Dairy’s response unfolded in stages. The company first announced a limited recall of its soft ricotta and requeson cheese, following confirmation that these fresh cheeses were contaminated with Listeria. That initial action, detailed in an FDA notice on the dairy’s soft cheese recall, focused on products sold under the Clover Hill Dairy brand name with specific sell-by dates.
As investigators traced illnesses and tested additional samples, the company broadened the action dramatically. It later expanded the recall to all Clover Hill Dairy brand cheese, covering hard cheeses, soft cheeses, ricotta, cuajada varieties, and flavored cheeses. The company ceased production and distribution of all cheese products while investigations continue. Products reached consumers in Maryland, Washington, D.C., Virginia, North Carolina, New York, and New Jersey, primarily through small retailers and regional distributors that serve Hispanic and Latino communities.
The Maryland Department of Health suspended the facility’s operating license and is conducting a follow-up evaluation, according to a CDC press release. The state agency’s expanded advisory noted that the facility agreed to initiate a voluntary recall covering all cheese products and that production cannot resume until the plant demonstrates it can operate safely. Inspectors are reviewing sanitation procedures, environmental monitoring records, and any recent changes in equipment or ingredients that might have affected contamination patterns.
A separate layer of risk emerged through the supply chain. New York State Department of Agriculture and Markets inspectors sampled an 18-pound container of Clover Hill Dairy requeson cheese with a sell-by date of June 14, 2026, and confirmed it was contaminated with Listeria monocytogenes. That product had been repacked and sold under a different label at a New York retailer, illustrating how bulk cheese can move from a small processor into a variety of brands and storefronts. Regulators warned that consumers might not recognize the original producer’s name even if they had purchased the affected cheese.
Because Listeria can cause severe illness, especially in older adults, pregnant people, and those with weakened immune systems, both federal and state agencies have urged anyone who purchased Clover Hill Dairy cheese to check their refrigerators and freezers. Consumers are advised to discard any remaining product, avoid consuming cheese of uncertain origin that may have been repacked in stores, and clean and sanitize surfaces that may have come into contact with the recalled items. Healthcare providers in the affected states have also been alerted to watch for listeriosis symptoms, including fever, muscle aches, and gastrointestinal distress, in patients who report eating fresh or soft cheeses during the exposure window.
While the investigation continues, the Clover Hill case underscores long-standing concerns about persistent Listeria in small dairy plants and the challenges of detecting low-level, sporadic outbreaks that stretch across years. Public health officials say the combination of genetic sequencing, coordinated surveillance, and aggressive recalls remains the best tool for interrupting these prolonged contamination events before they claim more lives.
