Active Outbreak · 1 Death · Recall in Effect

Listeria Cheese Outbreak 2026

United States · Soft cheese (requesón) · CDC & FDA investigation
Source: CDC Listeria Outbreak · FDA Investigation. Not a medical authority. Verify with CDC.

About Listeria

Cause
Listeria monocytogenes (a bacterium)
Symptoms can start
Same day up to 10 weeks after eating
Most at risk
Pregnant people, 65+, weak immune systems, newborns
Treatment
Antibiotics (ampicillin / amoxicillin)

What is listeriosis?
Listeriosis is a serious infection caused by eating food contaminated with the bacterium Listeria monocytogenes. Unlike most food germs, Listeria can keep growing at cold refrigerator temperatures, which is why soft cheeses, deli meats, and other ready-to-eat foods are common sources. It is one of the leading causes of death from foodborne illness in the United States.

What are the symptoms?
In otherwise healthy people, Listeria may cause fever, muscle aches, nausea, vomiting, and diarrhea. In more serious (invasive) cases the infection spreads beyond the gut, causing high fever, stiff neck, confusion, loss of balance, and convulsions. Symptoms can appear the same day you eat contaminated food, or as long as 10 weeks later, which makes the source hard to trace.

If you are pregnant

Pregnant people are about 10 times more likely to get listeriosis, and the illness is especially dangerous. It often feels like a mild flu — fever, tiredness, aches — but the bacteria can pass to the baby and cause miscarriage, stillbirth, premature birth, or a life-threatening infection in the newborn. If you are pregnant, ate a recalled cheese in the past 10 weeks, and feel feverish or unwell, call your doctor right away. Early antibiotic treatment can protect the baby.

How is it treated?
Listeriosis is treated with antibiotics, usually ampicillin or amoxicillin, and treatment works best when started early. People with invasive infection often need to be hospitalized. Anyone in a high-risk group who develops fever and flu-like symptoms after eating a recalled product should seek care promptly and mention the exposure.

How to protect yourself
•Check your fridge for any recalled requesón, ricotta, or soft "queso fresco" style cheeses named above and throw them out.
•If you are pregnant, 65 or older, or have a weakened immune system, avoid soft cheeses unless the label clearly says they are made with pasteurized milk.
•Clean your refrigerator and any surfaces or containers that touched a recalled product — Listeria can survive and spread in the fridge.
•Heat leftovers and ready-to-eat foods until steaming hot (165°F) if you are in a high-risk group.
•Watch for symptoms for up to 10 weeks after eating a recalled food, and see a doctor if fever or flu-like illness appears.

Sources: CDC About Listeria · CDC Symptoms · CDC Prevention · FDA Outbreak Investigation

Treatments & Vaccines in Development

Listeria is treatable with antibiotics, and there is no human vaccine yet — prevention is about food safety and recalls. Here's the treatment and the early-stage vaccine research.

Ampicillin / amoxicillinAntibiotic
Standard of care
Generic — existing drugs

Listeriosis is treated with antibiotics, usually ampicillin or amoxicillin (sometimes with gentamicin for severe infection). Treatment works best when started early, so high-risk people — especially pregnant women — should seek care quickly after a known exposure. For pregnant patients, prompt antibiotics can protect the baby.

CDC clinical care →
mRNA-LNP Listeria vaccineVaccine (mRNA)
Early research
Academic research

There is no approved vaccine to prevent Listeria infection in people. The most promising research uses the same mRNA / lipid-nanoparticle technology as COVID vaccines to train immune cells against Listeria; it has protected mice in lab experiments but has not yet reached human trials. For now, prevention relies on food safety and recalls, not a vaccine.

Nature Communications →
Approved / in usePositive trial resultsIn clinical trialsEarly researchHalted