Medically Reviewed by Brunilda Nazario, MD on August 12, 2020
“Food poisoning” is a broad term that can actually cover a whole lot of different infections. Your exact symptoms and how bad they are will vary. They will depend on the kind of bacteria, virus, or parasite that’s infected you, how much is in your system, and how well your immune system is fighting it off. Despite the wide range of types, most cases of food poisoning cause some mix of the following: If you have a mild case, you might think you have a “stomach flu” or virus. You may get better without any treatment. But some people have such bad symptoms that they may need to go to the hospital. Cramps in your stomach and gut, diarrhea, and vomiting may start as early as 1 hour after eating tainted food and as late as 10 days or longer. It depends on what is causing the infection. Some other possible, common symptoms of a variety of food poisonings might include: Some symptoms mean you should seek medical help: You’ve probably heard of the some of the bad bugs that can cause food poisoning:
Botulism is a rare but severe type of bacterial food poisoning. Clostridium botulinum is the bacteria that causes botulism. It grows on food that hasn’t been cooked or stored at the right temperatures to kill it or stop it from growing. This sometimes happens with foods that have been canned at home. Babies can get it from foods that have bacteria in them, because they don’t have the natural defenses that older children and adults do. Honey is the most common food that can infect a baby with botulism -- never give it to a baby under 1 year of age. Symptoms might include: Call 911 if you see any symptoms of botulism in yourself or a loved one. Anyone who eats contaminated food can get ill from food poisoning. But just how sick you get depends on what the infection is, how much of it you’re exposed to, your age, and your health. Certain groups of people have a greater chance of getting seriously sick from food poisoning: To diagnose food poisoning, your doctor will review your medical history, including your symptoms, how long you’ve had them, and what foods you’ve eaten. They’ll also ask whether you’ve traveled, and they may ask whether anyone else at home has these symptoms. Based on what they find out, they may test your urine to see if you’re dehydrated. They may also take blood and stool samples to try and trace the organism that has caused your illness.
If they find out the organism, they may contact your local health department to see if there’s an outbreak. It’s not always possible to find the exact cause.
Viral gastroenteritis, or “stomach flu,” has several symptoms that are a lot like those of food poisoning, including: Just like with food poisoning, you may have a fever. But it will be a low-grade one (less than 101 F). Your head and muscles could also hurt. These symptoms often start within 1 to 3 days of when you catch the infection. They usually last just a day or 2, but can go on as long as 10 days. A mild case of food poisoning usually passes on its own with just rest and lots of fluids. But if you or a loved one has any signs of botulism or life-threatening illness, call 911 right away.
If I get food poisoning, how long after eating will I feel ill?
- Please tell me how long the incubation period is for common food poisoning symptoms.
The most common symptoms of food poisoning are nausea, vomiting, stomach pain, and diarrhea. These symptoms may also be accompanied by fever. The time between infection with the bacteria or virus which causes the food poisoning and the appearance of symptoms is called the incubation period. Incubation times differ depending on the bacteria, virus, or other cause of the food poisoning. For example, the incubation period for Norovirus, which has been a frequent cause of food poisoning in recent years, is between 24 and 48 hours. For Campylobacter, it’s two to seven days. Food poisoning caused by the toxins produced by bacteria when they multiply (such as enterotoxin produced by Staphylococcus aureus when it reproduces), natural poisons from mushrooms or fish, and chemicals such as histamine can cause vomiting and other symptoms immediately after intake. Note that incubation times for the same bacteria or virus can vary depending on the amount of contaminated food ingested and the physical health of the victims, among other factors. The most common symptoms are as described above. Symptoms such as nervous disorders like paralysis can be caused by the natural toxins found in pufferfish and mushrooms, however. In addition, histamine-producing bacteria can produce histamine from histidine, an amino acid found in red meat fish like tuna and skipjack. Consumption of this histamine can cause food poisoning symptoms like headache, rash, and fever.
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Food poisoning (foodborne illness) is caused by bacteria or viruses found in food.
Millions of Americans get food poisoning each year.
Food poisoning symptoms often look like stomach flu (gastroenteritis). Many people with a mild case think they have stomach flu or a virus.
What causes food poisoning?
Most food poisoning is caused by eating food that has certain types of bacteria or viruses. When you eat these foods, the bacteria keeps growing in your digestive tract. This causes an infection.
Foods can also make you ill if they have a toxin or poison made by bacteria growing in the food.
Several types of bacteria can cause food poisoning. Among the more common bacteria are:
Salmonella and Campylobacter
- May be found in meat, poultry, and eggs that are raw or not cooked long enough (undercooked)
- Can be found in dairy products that haven’t gone through a high-heat process to kill bacteria (are unpasteurized)
- Can be found in raw fruits and vegetables
Clostridium perfringens
- May be found in raw meat, poultry, eggs, or unpasteurized dairy foods
- Can be found in vegetables and crops that have touched soil
- Can cause food poisoning when soups, stew, and gravies made with meat, fish, or poultry are not refrigerated
Listeria
- May be found in unpasteurized milk and soft cheeses made with unpasteurized milk
- May also be found in deli meats, hot dogs, and store-made deli salads
Staphylococcus aureus
- Can spread to food when touched by someone with the bacteria
- Can cause infection when foods such as meats and egg salad are not refrigerated
Escherichia coli (E. coli)
- Can cause infection if you eat beef that is undercooked, mainly ground beef
- Can be found in unpasteurized milk
- Can be found in food or water that is contaminated
You can also get food poisoning from viral diseases such as Hepatitis A. These viral diseases:
- Can pass from an infected person’s hands to the hands of food workers or into waste water (sewage)
- Can spread when shellfish and other foods have touched unsafe, dirty water
Botulism is a rare but deadly form of food poisoning. It is caused by a bacteria (clostridium botulinum) that is found all over, even in soil and water.
Botulism can happen when:
- You eat low-acid foods that are not properly canned or preserved at home. These foods include meat, fish, poultry, or vegetables.
- Infants eat raw honey or corn syrup. Babies younger than 1 year old should never have honey or corn syrup.
Who is at risk for food poisoning?
Anyone can get food poisoning. But some people are more likely to get it than others. They are also at greater risk of getting very ill from it. This is because their body’s disease-fighting system (immune system) doesn’t work well.
People who are at greater risk include:
- Young children. Their immune systems aren’t fully developed yet.
- Older adults. Their immune systems don't work as well. Age-related changes in our senses of taste and smell also make it easier to eat contaminated food by mistake.
- Pregnant women. A woman’s immune system changes during pregnancy. The unborn baby is also at risk.
- People with long-term (chronic) disease. People with diseases such as diabetes or cancer have weaker immune systems.
What are the symptoms of food poisoning?
Food poisoning symptoms can look like the symptoms of stomach flu (gastroenteritis). Many people with mild cases of food poisoning think they have stomach flu.
The time it takes food poisoning symptoms to start can vary. Illness often starts in about 1 to 3 days. But symptoms can start any time from 30 minutes to 3 weeks after eating contaminated food. The length of time depends on the type of bacteria or virus causing the illness.
Each person’s symptoms may vary. Symptoms can range from very mild to very serious. They can last from a few hours to several days. Symptoms may include:
- Belly cramps
- Watery or bloody diarrhea
- Nausea and vomiting
- Headache
- Fever
- Belly bloating and gas
Food poisoning symptoms may look like other health problems. Always see your healthcare provider to be sure.
How is food poisoning diagnosed?
Your healthcare provider will ask you when you became sick, what your symptoms are, and what foods you have eaten.
Your provider will also look at your past health. He or she will give you a physical exam.
You may have lab tests to find out what bacteria caused your illness. In some cases the cause can’t be found.
How is food poisoning treated?
Most mild cases of food poisoning are treated the same as stomach flu (gastroenteritis). If you have diarrhea or vomiting, you may lose a lot of fluids (get dehydrated). The goal is to replace your lost fluids and ease your symptoms.
For some types of bacterial food poisoning, your health care provider may give you a medicine that fights bacteria (an antibiotic). Antibiotics don’t work on infections caused by a virus.
In severe cases you may need to be hospitalized.
Call your health care provider if you can’t keep fluids down. Also call if your symptoms don’t go away.
What can I do to prevent food poisoning?
To prevent food poisoning, wash your hands often. Also prepare and store food safely.
Always wash your hands after:
- Using the toilet
- Changing diapers
- Smoking
- Blowing your nose
- Coughing or sneezing
- Touching animals
When preparing food be sure to:
- Wash your hands for at least 20 seconds with warm soapy water before and after touching raw meat, poultry, shellfish, fish, eggs, or produce.
- Wash all fruits and vegetables well before eating
- Use plastic cutting boards for cutting raw fish, poultry, or meat. They are easier to keep clean.
- All utensils and surfaces should be washed with warm soapy water before and after they are used to prepare food. One quart of water mixed with 1 teaspoon of bleach can be used to sanitize surfaces and utensils.
- Cook poultry, beef, and eggs for the right amount of time before eating
- Keep raw meat, poultry, seafood, and their juices away from other foods
- Use a meat thermometer to ensure foods are cooked to an appropriate internal temperature.
When choosing food to eat be sure to:
- Not have any food made from unpasteurized milk
- Not have any food made from raw or undercooked eggs, poultry and meat
When storing food be sure to:
- Refrigerate or freeze raw and cooked perishable foods right away. If they are at room temperature for more than 2 hours, consider them unsafe to eat.
- Refrigerators should be set at 40°F or below. Set freezers at 0°F.
- Keep fruits and vegetables, cooked foods, and prepared foods away from raw meat and raw eggs
- Refrigerate mayonnaise, salad dressings, and any foods that have them
- Throw out food if you don’t know how long it’s been left out of the fridge
- Throw out food if you’re not sure it is bad
Key points about food poisoning
- Food poisoning is caused by bacteria and viruses found in food.
- Symptoms may look like stomach flu (gastroenteritis).
- Treatment focuses on replacing fluids and easing nausea and vomiting.
- In severe cases you may need to be hospitalized.
- To prevent food poisoning, wash your hands often. Also prepare and store food safely.
Next steps
Tips to help you get the most from a visit to your healthcare provider:- Know the reason for your visit and what you want to happen.
- Before your visit, write down questions you want answered.
- Bring someone with you to help you ask questions and remember what your provider tells you.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.
- Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
- Ask if your condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if you do not take the medicine or have the test or procedure.
- If you have a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your provider if you have questions.