
According to the Centers for Disease Prevention and Control, symptoms of listeria usually begin within 24 hours after eating the contaminated food and can last one to three days.
What is listeria?
Listeria is a disease brought on by consuming foods contaminated with the Listeria monocytogenes bacterium. Listeria infection or listeriosis is rare but can be fatal in susceptible individuals, such as older people and those with compromised immune systems. It might be harmful to pregnant individuals and their unborn children.
There are two main types of listeriosis:
- Noninvasive listeriosis (febrile gastroenteritis): A mild form of illness that primarily affects normally healthy individuals. Diarrhea, fever, headaches, and myalgia (muscle pain) are some of the symptoms of noninvasive listeriosis. It has an extremely short incubation period. The consumption of foods high in L. monocytogenes has typically been a factor in outbreaks of this illness.
- Invasive listeriosis: A more severe form of the disease that affects specific high-risk groups. They include pregnant people; people undergoing treatment for AIDS, cancer, or organ transplants; older people, and parents of young children. The hallmarks of this type of sickness include severe symptoms and a high death rate (20 to 30 percent). Some of the symptoms include fever, myalgia, septicemia, and meningitis. The incubation period, which is normally one to two weeks long, can last anywhere between a few days and up to 90 days.
What are the symptoms of listeriosis?
Serious listeriosis infections have the potential to spread to the brain or bloodstream and may result in sepsis, meningitis, or encephalitis.
Symptoms of listeriosis include:
How are people infected with listeriosis?
Listeria monocytogenes infection occurs when people consume or handle contaminated food. The bacteria get to the mouth or other openings from the hands. If a pregnant person consumed contaminated food while pregnant, their babies may contract the infection in the womb or at delivery.
Numerous foods can become contaminated by the bacteria, such as:
- Raw meat
- Ready-to-eat processed meat, such as hot dogs and deli meat (both items served at deli counters and in factory-sealed packets)
- Raw vegetables
- Chilled patés
- Ready to eat uncooked and smoked seafood
- Salads that have been prepared or kept, such as coleslaw and fruit salad
- Melons
- Unpasteurized milk and milk products or soft cheeses produced from them
Listeria monocytogenes bacterium can be destroyed by cooking, pasteurization, and by some disinfectant agents. Reheating ready-to-eat foods to a steaming temperature makes them safe to consume.

SLIDESHOW
Bacterial Infections 101: Types, Symptoms, and Treatments See SlideshowWho are at risk of listeriosis?
Listeriosis can affect anyone. It is less dangerous for those with a strong immune system.
The following people are at a high risk of dying or getting severely ill due to listeriosis:
How to prevent listeriosis
Those who are more vulnerable should adhere to the following food safety precautions to prevent infection:
- Only consume or serve completely cooked food derived from animal products
- Dairy products should have a pasteurization statement on the label before consumption
- Do not consume raw (unpasteurized) milk or products made with it (for example, unpasteurized feta, brie, and queso fresco)
- Wash fruits and vegetables
- Store prepared foods at 40 °F or lower temperatures
- Do not combine vegetables and raw meat
- After handling raw foods, wash your hands, knives, and cutting boards
- Cook ready-to-eat meals, such as hot dogs and leftovers, completely until they are piping hot
- Avoid eating prepackaged salads, meats, or cheeses from delis, or reheat them to a steaming temperature before eating
Get the Facts about Listeria. https://www.fda.gov/animal-veterinary/animal-health-literacy/get-facts-about-listeria
Listeriosis. https://www.who.int/news-room/fact-sheets/detail/listeriosis
Listeriosis in Infants, Children & Pregnant People. https://www.healthychildren.org/English/health-issues/conditions/infections/Pages/Listeriosis-Infection.aspx
Listeria (Listeriosis). https://www.cdc.gov/listeria/symptoms.html
Listeria (food poisoning). https://www.pregnancybirthbaby.org.au/listeria-food-poisoning
Top How Long Do Listeria Symptoms Last Related Articles
9 Food Poisoning Myths That Are Wrong
Knowing too much wrong information about a condition is just as bad as knowing too little about a disease. That's why we took it upon ourselves to debunk these 9 food poisoning myths.Bacterial Infections 101
Get more information on bacterial skin infections, which bacteria cause food poisoning, sexually transmitted bacteria, and more. Explore the most common bacterial infections.Food Poisoning
Food poisoning is common but can also be life-threatening. Food poisoning symptoms include stomach cramps, diarrhea, and vomiting. Read about different types of food poisoning, treatment, and tips for prevention.Food Poisoning Quiz
What causes food poisoning? Can it be prevented? Take this quiz to learn about food safety and how to guard yourself against food poisoning.Food and Health: Foods Most Likely to Give You Food Poisoning
Every year, 1 in 6 people in the U.S. get a foodborne illness. Find out which foods sicken the most number of Americans, and how.Is It a Stomach Virus or Food Poisoning?
A stomach virus is also called stomach flu or gastroenteritis. It is a viral infection that infects the tummy and the gut. Food poisoning is also often called gastroenteritis and may present symptoms like stomach virus/stomach flu. However, food poisoning is caused by consuming food or drinks that may be contaminated with bacteria.Listeria (Listeriosis)
Listeria is a type of bacteria that can cause food poisoning. Listeriosis symptoms include diarrhea, nausea, and fever. Pregnant women are 20 times more likely than other healthy adults to get listeriosis. Listeria infection is treated with antibiotics.
Salmonella Food Poisoning
Salmonella infection (salmonellosis) is typically caused by the consumption of contaminated foods. Symptoms of salmonellosis include fever, vomiting, diarrhea, and abdominal pain. Salmonellosis typically resolves on its own in four to seven days. It's important to increase one's fluid intake to compensate for the fluid lost by vomiting and/or diarrhea.Salmonella Food Poisoning Treatment, Symptoms
What is Salmonella? What are the best treatments for Salmonella, and what are its symptoms? From food poisoning to typhoid fever, learn about this common pathogen. Discover how to prepare food without Salmonella risk, and what to do if you get a Salmonella infection.Stomach Flu vs. Food Poisoning
The stomach flu (viral gastroenteritis) and food poisoning are not the same infections. However, they do have a few similar symptoms, for example:
- Nausea
- Vomiting
- Diarrhea
- Fever
- Abdominal (stomach) pain and cramping.
Symptoms and signs of food poisoning show up earlier (2 hours up to a couple of days) in comparison to the stomach flu in which symptoms may take 4 hours up to 48 hours (2 days) before symptoms begin. Medical treatment for the stomach flu and food poisoning generally is not necessary. A bland diet, drinking plenty of fluids, and rest may be the only treatment necessary.
What Foods Contain Listeria?
Listeria is a bacterium that is commonly found in soil and water, which may contaminate the following foods.What Medicine Helps With Food Poisoning?
Learn what medical treatments can help ease your food poisoning symptoms and speed up your recovery. Many cases of food poisoning never get an official diagnosis from the doctor. If you need to visit your doctor for food poisoning, they will diagnose you based on your symptoms. Food poisoning is a common illness that usually resolves within one to two days. Learn the signs of food poisoning, what causes food poisoning, and what you can do to treat food poisoning.Where Does Bacterial Meningitis Come From?
Bacterial meningitis is characterized by inflammation around your brain and spinal cord that leads to dangerous — and sometimes deadly — pressure in this area. Bacterial meningitis comes from person-to-person contact with an infected person.