What is food poisoning?
Food poisoning is an illness caused by eating foods that have harmful germs in them. These germs are mostly found in raw meat, chicken, fish, and eggs, but they can spread to any type of food. They can also grow on food that's left out on counters or outdoors or is stored too long before you eat it. Sometimes food poisoning happens when people don't wash their hands before they touch food.
Most of the time, food poisoning is mild and goes away after a few days. All you can do is wait for your body to get rid of the germ that's causing the illness. But some types of food poisoning may be more serious, and you may need to see a doctor.
What causes it?
Food poisoning is caused by eating or drinking food contaminated by harmful germs, such as bacteria, parasites, and viruses. Harmful germs may get into food when it's prepared or processed or when it's washed with contaminated water.
What are the symptoms?
The first symptom of food poisoning is usually diarrhea. You may also feel sick to your stomach, vomit, or have stomach cramps. Some food poisoning can cause a high fever and blood in your stool. If you vomit or have diarrhea a lot, you can get dehydrated.
How is it diagnosed?
If you go to the doctor, you will be asked about your symptoms and general health. You'll get a physical exam. Your doctor will ask where you've been eating and whether anyone who ate the same foods is also sick. Sometimes the doctor will take stool or blood samples to be tested.
How is food poisoning treated?
Treatment for food poisoning focuses on managing symptoms, like vomiting and diarrhea. You'll need to rest and get plenty of fluids to prevent dehydration. Diarrhea medicines may help, but they shouldn't be used for children or people with a high fever or bloody diarrhea. For severe dehydration, you may need treatment in the hospital.
How can you prevent it?
You can prevent most cases of food poisoning with simple steps. For example, wash your hands before touching foods. Separate raw meat from other foods, and make sure meats are cooked well. Refrigerate leftovers right away.
Food poisoning is caused by eating or drinking food contaminated by harmful germs, such as bacteria, parasites, and viruses.
Germs can get into food:
- When meat is processed.
Bacteria live in the intestines of healthy animals used for food. Sometimes the bacteria get mixed up with the parts of those animals that we eat.
- When food is watered or washed.
If the water that's used to irrigate or wash fresh fruits and vegetables has germs from animal manure or human sewage in it, those germs can get on the fruits and vegetables.
- When food is prepared.
When there are germs on the hands of someone who touches the food, or if the food touches other food that has germs on it, the germs can spread. Germs from raw meat can get onto vegetables if you use the same cutting board for both, for example. Home-canned foods that haven't been prepared properly may contain germs.
You can prevent most cases of food poisoning by being careful when you prepare and store food.
The following steps can help prevent food poisoning.
- Shop safely.
Don't buy canned foods that are dented, leaking, or bulging. Get your refrigerated and frozen foods at the end of your shopping trip. Bag raw meat, poultry, and fish separately from other food items. And try to go straight home after you shop, so you can store food properly.
- Prepare foods safely.
Wash your hands before and after handling food. Wash cutting boards with hot soapy water. Wash fruits and vegetables, but don't wash raw meat. Follow procedures for safe home canning to avoid contamination.
- Store foods safely.
Cook, refrigerate, or freeze meat, poultry, eggs, fish, and ready-to-eat foods within 2 hours. Make sure your refrigerator is set at 40°F (4°C) or colder.
- Separate raw food from other food.
Keep raw meat, poultry, eggs, fish, and shellfish away from other foods, surfaces, utensils, and serving plates.
- Thaw meat and seafood safely.
Thaw these foods in the refrigerator, not at room temperature. And cook food right away after thawing.
- Avoid eating raw or undercooked foods.
Do not eat raw or partially cooked eggs (including cookie dough), raw (unpasteurized) milk, cheeses made with raw milk, or unpasteurized juices.
- Cook foods safely.
Use a clean meat thermometer to make sure that foods are cooked to a safe temperature. Reheat leftovers to at least 165°F (74°C). Don't eat undercooked hamburger. Bring sauces, gravies, and soups to a boil when reheating. And be aware of the risk of food poisoning from raw fish (including sushi), clams, and oysters.
- Serve foods safely.
Keep cooked hot foods hot [140°F (60°C) or above] and cold foods cold [40°F (4°C) or below]. And chill leftovers as soon as you finish eating.
- Follow labels on food packaging.
These labels provide information about when to use the food and how to store it.
- When in doubt, throw it out.
If you aren't sure if a food is safe, don't eat it. Reheating food that is contaminated won't make it safe. Don't taste suspicious food. It may smell and look fine. But it still may not be safe to eat.
- Make smart restaurant choices.
- Note the general cleanliness of the facility and staff. If you aren't confident that conditions are sanitary, leave.
- Find out the inspection scores of selected restaurants. (They are sometimes posted in the restaurant.) Restaurants are inspected by the local health department for cleanliness and proper kitchen procedures.
The first symptom of food poisoning is usually diarrhea. You may also feel sick to your stomach, vomit, or have stomach cramps. Some food poisoning can cause a high fever and blood in your stool.
If you vomit or have diarrhea a lot, you can get dehydrated. This means that your body has lost too much fluid.
Some types of food poisoning have different or more severe symptoms. These can include weakness, numbness, confusion, or tingling of the face, hands, and feet.
How you feel when you have food poisoning mostly depends on how healthy you are and what germ is making you sick.
For very young and very old people, symptoms may last longer. Even the types of food poisoning that are typically mild can be life-threatening. This may also be true for people who are pregnant or who have weak immune systems, such as those who have long-lasting (chronic) illnesses.
You may become ill with food poisoning after you eat food that contains bacteria, viruses, or other harmful germs.
After you eat a contaminated food, you may notice symptoms after a few hours or days. The harmful germs pass through the stomach into the intestine and start to multiply. Some organisms stay in the intestine. Some produce a toxin that is absorbed into the bloodstream. And others infect body tissues. Your symptoms depend on the type of germ that has infected you.
Diarrhea and vomiting are a normal response as the body tries to rid itself of harmful germs.
Most of the time, food poisoning is mild and passes in a few days. But the symptoms of some types of food poisoning may be more severe. In rare cases, food poisoning can cause kidney or joint damage.
When to Call a Doctor
Call 911 or other emergency services immediately if:
- You have sudden, severe belly pain.
- You have signs of severe dehydration. These include little or no urine; sunken eyes, no tears, and a dry mouth and tongue; fast breathing and heartbeat; feeling very dizzy or lightheaded; and not feeling or acting alert.
- You think you may have food poisoning from a canned food and you have symptoms of botulism (blurred or double vision, trouble swallowing or breathing, and muscle weakness).
Call your doctor now if:
- You have severe diarrhea (large amounts of loose stool every 1 to 2 hours) that lasts longer than 2 days if you are an adult.
- You have vomiting that lasts longer than 1 day if you are an adult.
- You are pregnant and believe that you have been exposed to listeriosis or toxoplasmosis.
Talk to your doctor if:
- You have symptoms of mild dehydration (dry mouth or passing only a little urine) that get worse even with home treatment.
- You have a fever.
- You aren't feeling better after 1 week of home treatment.
If you think you have eaten contaminated food, call your local Poison Control Center. They can answer questions and tell you what to do next.
Watchful waiting is a wait-and-see approach.
Watchful waiting may be okay if you have diarrhea, stomach cramps, and other symptoms of a stomach infection (gastroenteritis). Most people recover from these gastrointestinal illnesses at home in several days without medical treatment. Likewise, some cases of bacterial food poisoning are mild and pass in several days.
Check your symptoms
Exams and Tests
Most people don't go to the doctor to get diagnosed. That's because most food poisoning is mild and goes away after a few days. You can usually assume that you have food poisoning if others who ate the same food also got sick.
If you go to the doctor, you'll be asked about your symptoms and health and get a physical exam. Your doctor will ask where you've been eating and whether anyone who ate the same foods is also sick. Sometimes the doctor will take stool or blood samples to be tested.
If you think you have food poisoning, call your local health department to report it. This could help keep others from getting sick.
Treatment for food poisoning focuses on managing symptoms, such as vomiting and diarrhea. You'll need to rest and get plenty of fluids to prevent dehydration. The goal of treatment is to replace fluids and electrolytes lost through vomiting and diarrhea.
If dehydration is severe and can't be managed at home, you may need treatment in the hospital. Fluids and electrolytes may be given to you through a needle in your vein.
Medicines that stop diarrhea (such as Imodium) can help with your symptoms. But these medicines shouldn't be used for children or for people with a high fever or bloody diarrhea. Antibiotics are rarely used. They're only given for certain types of food poisoning or in severe cases.
In most cases, food poisoning goes away on its own in a few days.
Most cases of food poisoning will go away in a few days with rest and care at home. Dehydration is the most frequent complication of food poisoning. Older persons and children should take special precautions to prevent it.
The following information will help you recover.
- Drink plenty of fluids.
Choose water and other clear liquids until you feel better. You can take frequent sips of a rehydration drink (such as Pedialyte) to prevent dehydration.
Sports drinks, soda pop, and fruit juices contain too much sugar and not enough of the important electrolytes that are lost during diarrhea. These kinds of drinks shouldn't be used to rehydrate.
- Eat small amounts of food.
When you feel like eating again, start out with small amounts of food. This will help you to get enough nutrition.
Caring for your child
Dehydration is the most frequent problem caused by food poisoning. Be extra careful to prevent dehydration in children.
For children who are breastfed or bottle-fed, keep giving the regular breast milk or formula feeding as much as possible. You may have to feed more often to replace lost fluids. Give an oral rehydration solution (ORS), such as Pedialyte, between feedings only if you see signs of dehydration.
For older children, give them sips of water or a rehydration drink often. And offer small amounts of food when they feel like eating again.
Current as of: February 9, 2022
Author: Healthwise Staff
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine