What Are the Symptoms of Listeria?
Listeria can cause two kinds of illness. The CDC says intestinal illness usually starts within 24 hours of eating contaminated food, typically with diarrhea and vomiting, and lasts 1 to 3 days. Invasive listeriosis happens when the bacteria spread beyond the intestines, with symptoms usually starting within 2 weeks, including fever and flu-like symptoms such as muscle aches and fatigue, headache, stiff neck, confusion, loss of balance and seizures.
The CDC estimates 1,250 people in the United States get sick from Listeria every year, and says more than half of infections occur among people 65 and older. People with a weakened immune system make up 75 percent of people with Listeria infection, infection almost always leads to hospitalization, and the CDC says 1 in 6 people in that group with Listeria infection die.
For invasive illness, the CDC lists foods including queso fresco and other soft cheeses, raw sprouts, melons, hot dogs, pâtés, deli meats, smoked fish and raw milk.
Sources checked September 15, 2026. Every point below links the page it came from.
The sources behind this answer
- Government sourceThe CDC lists symptoms of invasive Listeria illness as fever and flu-like symptoms such as muscle aches and fatigue, headache, stiff neck, confusion, loss of balance and seizures. CDC ↗
- Government sourceThe CDC says invasive listeriosis happens when Listeria spreads beyond the intestines, and symptoms usually start within 2 weeks after eating contaminated food. CDC ↗
- Government sourceThe CDC says Listeria intestinal illness usually starts within 24 hours of eating contaminated food, lasts 1 to 3 days and typically includes diarrhea and vomiting. CDC ↗
- Government sourceThe CDC estimates 1,250 people in the United States get sick from Listeria every year, and says more than half of infections occur among people 65 and older. CDC ↗
- Government sourceThe CDC says people with weakened immune systems make up 75 percent of Listeria infections, infection almost always leads to hospitalization, and 1 in 6 in this group die. CDC ↗
- Government sourceThe CDC lists foods linked to invasive Listeria illness including soft cheeses such as queso fresco, raw sprouts, melons, hot dogs, pâtés, deli meats, smoked fish and raw milk. CDC ↗
Sources checked September 15, 2026. A brand statement is the company’s own claim, which we report but have not verified. Our grades are model-based estimates, not lab tests.