A multi-state outbreak of Listeria monocytogenes infections linked to requeson cheese, a soft ricotta-style product, has affected 12 people across four states since March 2023, resulting in 10 hospitalizations and one death. The outbreak, which the FDA and CDC are still investigating, highlights how contamination in soft cheese products can persist undetected for years before triggering a public health response.

The outbreak centers on requeson cheese manufactured by Clover Hill Dairy, LLC of Mechanicsville, Maryland. On June 18, 2026, the company expanded its recall to include all cheese products manufactured at their facility, not just requeson. This sweeping action came after environmental samples and product samples tested positive for the outbreak strain of Listeria monocytogenes.

Which Products and Brands Are Affected?

The recall involves multiple brands and distribution channels, making it difficult for consumers to identify affected products. Clover Hill Dairy cheese products are sold under their own brand name as well as under several other labels when repackaged by distributors. Additionally, La Ceiba Foods Latin Market Inc. repackaged Clover Hill requeson cheese and distributed it under the La Colonia and Selectos Latinos brand names.

• Clover Hill Dairy Products: All soft ricotta, requeson, cuajada, and hard cheese varieties manufactured at the facility are included in the recall, sold in clamshell containers and bulk buckets
• Repackaged Brands: Products may be relabeled under brand names including KESSO, QUESOS LA RICURA, IZALCO, DE MI PUEBLO, and RIO LINDO when distributed by third parties
• La Ceiba Foods Products: Requeson Salvadoreño and Requeson Mexicano marketed under La Colonia and Selectos Latinos brands were distributed to supermarkets, retail stores, and restaurants in Maryland, Virginia, and Washington, D.C. between May 11 and June 1, 2026
• Nelson & Isa Lacteos Products: Requeson cheese sold at retail locations in New York from May 15 to May 28, 2026 was also recalled

The geographic distribution of recalled products spans Maryland, New Jersey, New York, North Carolina, Virginia, and Washington, D.C., though the FDA notes that products could have been distributed to additional states beyond those confirmed.

What Are the Symptoms of Listeria Infection?

Listeria monocytogenes can cause a serious infection called listeriosis, with symptoms that may appear anywhere from the same day of exposure to as late as 10 weeks after eating contaminated food. Most people experience mild symptoms initially, but the infection can progress to a severe form in vulnerable populations.

Mild symptoms include fever, muscle aches, nausea, tiredness, vomiting, and diarrhea. However, if the infection develops into severe listeriosis, symptoms can include headache, stiff neck, confusion, loss of balance, and convulsions. Pregnant women typically experience only fever, fatigue, and muscle aches, but Listeria infection during pregnancy can lead to miscarriage, stillbirth, premature delivery, or life-threatening infection of the newborn.

Listeria is most dangerous for pregnant women, newborns, adults aged 65 or older, and people with weakened immune systems. Other people can be infected, but they rarely become seriously ill. Of the 10 people interviewed during the outbreak investigation, 9 reported eating cheese, and 2 reported eating requeson made by Clover Hill Dairy.

How to Protect Yourself During a Listeria Outbreak

• Check Your Refrigerator and Freezer: Look for any recalled cheese products and do not eat them. Return them to the place of purchase or throw them away. If you froze cheese without the original packaging and cannot determine if it is part of the recall, discard it to be safe
• Clean and Sanitize Surfaces: If recalled cheese touched any surfaces, containers, or utensils in your kitchen, carefully clean and sanitize them. Listeria can survive in refrigerated temperatures and easily spreads to other foods and surfaces
• Avoid High-Risk Soft Cheeses: If you are pregnant, aged 65 or older, or have a weakened immune system, do not eat any queso fresco-type cheese, including soft ricotta or requeson, until the outbreak is fully resolved
• Seek Medical Care if Symptomatic: If you develop symptoms of listeriosis, contact your healthcare provider right away to report your symptoms and receive appropriate care

Why Did This Outbreak Go Undetected for So Long?

The outbreak investigation revealed a troubling timeline. Sick people's samples were collected on dates ranging from March 6, 2023, to June 2, 2026, meaning cases occurred over more than three years before the outbreak was formally identified and recalled. Environmental samples collected by the Maryland Department of Health tested positive for Listeria monocytogenes on June 15, 2026, and a second environmental sample from Clover Hill Dairy tested positive on June 24, 2026.

This extended timeline suggests that the contamination persisted at the manufacturing facility for an extended period, potentially affecting multiple batches of cheese distributed across multiple states. The delay in detection underscores a critical gap in food safety monitoring for soft cheese products, which are known to be higher-risk foods for Listeria contamination due to their moisture content and lack of heat treatment during production.

The FDA and CDC investigation remains ongoing, and health officials continue to work with state and local partners to identify additional cases and prevent further illnesses. Consumers who purchased requeson or other soft cheeses from affected brands during the specified time periods should take immediate action to check their homes and follow the safety guidance provided by health authorities.