4 common bacterial infections that cause food poisoning and how to avoid it
- Four types of bacteria that cause food poisoning are campylobacter, salmonella, E. coli, and listeria.
- You can become infected with campylobacter, which causes 1.3 million US cases of food poisoning each year, from undercooked poultry.
- You can get E. coli from eating ground beef, unpasteurized milk, and fresh produce like spinach.
- This article was medically reviewed by Rudolph Bedford, MD, a gastroenterologist at Providence Saint John's Health Center in Santa Monica, California.
Food poisoning occurs when you eat or drink something that has been contaminated with harmful bacteria or viruses. Nearly 1 in 6 people get food poisoning each year, but most cases are mild and will get better with rest and hydration. However, some severe cases require medical attention.
This article covers four of the most common bacteria that cause food poisoning, and how to treat and prevent infections.
What is Campylobacter?
Campylobacter is a kind of bacteria that lives in the intestines of animals, especially poultry like chicken and turkey. You can get campylobacter from eating undercooked poultry or shellfish, or from drinking water contaminated with feces from infected humans or animals.
It is one of the most common causes of food poisoning — about 1.3 million people in the US get sick from Campylobacter each year.
Campylobacter usually won't make you sick right away — it takes 2 to 5 days for the infection to spread and cause symptoms. After that, symptoms usually last between 2-10 days and include:
- Diarrhea, which may be bloody
- Vomiting
- Stomach cramps
- Fever
Campylobacter treatment
"Most people will get better on their own," says Darria Long, MD, a clinical assistant professor at the University of Tennessee School of Medicine. "The important thing is to ensure adequate hydration and maintaining electrolyte balance," Long says.
To get enough electrolytes, it may help to drink a formula like Pedialyte, which contains the electrolyte salts that help you absorb water. Typically people start feeling better after a week.
"Those who become severely ill may need antibiotics," Long says, so if you have severe symptoms like bloody diarrhea and high fever, or aren't getting better, you may need to see a doctor.
How to prevent campylobacter infection
"Since poultry is the main source, careful handling of poultry is crucial," Long says. Long recommends these steps to avoid campylobacter poisoning:
- Don't rinse off your chicken before you cook it, as this can spread more bacteria onto surfaces and your hands.
- Make sure you cook poultry to an internal temperature of 165 degrees Fahrenheit.
- Wash any utensils you use to handle raw meat in hot, soapy water.
What is salmonella?
Each year, there are about 1.35 million cases of salmonella in the USUnited States, making it one of the most common causes of food poisoning. Salmonella is a type of bacteria that lives in human and animal intestines and can contaminate many different types of foods. Raw fruits, vegetables, eggs, and all types of meat can be sources of salmonella.
Symptoms of salmonella poisoning can hit you 12 to 72 hours after eating contaminated food and can last for up to a week. Some of the most common salmonella symptoms are:
- Diarrhea
- Vomiting
- Stomach cramping
- Fever
Salmonella treatment
"Salmonella infections generally aren't treated with antibiotics," Madsen says. "We give IV fluids if a person is dehydrated as well as anti-nausea medications if a person is experiencing a lot of nausea and vomiting." Doctors don't usually prescribe antibiotics because they can make salmonella stay in your system longer.
But for some severe cases, where patients have high fevers and extreme dehydration from vomiting and diarrhea, they may be treated with antibiotics for a week, Madsen says. "Antibiotics may also be necessary for people with compromised immune systems or for older patients."
In most cases of salmonella food poisoning, symptoms aren't severe and will go away on their own, Long says. "However, if someone is vomiting so much that they cannot keep down fluids, having bloody diarrhea, severe abdominal pain, is lethargic, or having any other concerning symptoms that are not improving, then you should seek medical care."
How to prevent salmonella infection
"The best way to avoid salmonella infections is to avoid raw meat and eggs," Madsen advises, "Salmonella can be carried on fruits and vegetables as well, so these should always be washed before eating."
What is E. coli?
Escherichia coli is a type of bacteria that lives in the intestines of both humans and animals and helps to digest food. It causes 265,000 cases of food poisoning each year in the US. Though certain strains of E. coli are helpful, others can cause illness and can even be life-threatening.
You can get E. coli from eating contaminated foods, particularly ground beef, unpasteurized milk, and fresh produce like spinach and lettuce. If you get E. coli poisoning, your symptoms may start as soon as the next day or can take up to 10 days to show up after you eat contaminated food.
The most common symptoms of E. coli are:
- Severe and sometimes bloody diarrhea
- Vomiting
- Stomach pain
E. coli treatment
Treating an E. coli infection doesn't usually require a trip to the doctor.
"E. coli infections are typically not treated with antibiotics, as antibiotics can actually make the symptoms of an E. coli infection worse," says Troy Madsen, MD, a professor of emergency medicine at the University of Utah. This is because when E. coli bacteria die off quickly, they can release large amounts of toxins into your body.
Instead, doctors will give you IV fluids if you are dehydrated and treat the symptoms of the infection while your body fights it off, Madsen says. People generally recover after 5 to 7 days.
In some cases, E. coli can cause a life-threatening kidney condition called Hemolytic uremic syndrome (HUS). Common symptoms of HUS are less frequent urination, dark-colored urine, and paleness in the face. If this happens, you should get medical help immediately.
How to prevent E. coli infection
"In order to avoid E. coli infections, always cook meat thoroughly and avoid raw milk," Madsen says. "E. coli can be on the surfaces of raw fruits and vegetables as well, so it's always important to wash fruits and vegetables before eating them."
What is listeria?
Listeria poisoning is usually caused by a type of bacteria called listeria monocytogenes, which lives in many environments including water, soil, and animal feces. This bacteria causes 1,600 US cases of food poisoning each year. The most common ways people get listeria are by eating:
- Contaminated soft cheeses like brie or queso fresco
- Contaminated deli meats or hot dogs
- Raw milk
- Contaminated fruits and vegetables
After eating food contaminated with listeria, your symptoms may start within a week, but in some cases, they can take more than a month to set in. The symptoms of listeria are generally diarrhea and fever.
Listeria treatment
Most cases of a listeria infection are mild and don't require any treatment. Typically people start to feel better in a few days. But you should exercise extreme caution if you are pregnant or immunocompromised.
If you are pregnant and get listeria, you should get treated with antibiotics as soon as possible to keep the infection from affecting the baby. Pregnant people may feel fatigue, fever, and aching muscles as symptoms of listeria.
For more information check out Insider's article on foods to avoid while pregnant.
How to prevent listeria infection
If you are in a high-risk group for listeria, you "should avoid soft cheeses, deli meats and hot dogs unless they've been heated to an internal temperature of 165 right before you serve," Long says.
People who aren't high-risk should follow normal precautions — make sure to cook meat thoroughly and wash hands while handling food.
Takeaways
Most cases of food poisoning are relatively mild and should clear up within a few days. If your symptoms get worse or last more than a week, call your doctor to see if you need treatment.
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