Food poisoning is a nasty illness to come down with, especially when it is serious and/or if you are away from home when it happens. You may encounter this disease when you eat or drink food or water that has been contaminated by viral, bacterial, or parasitic agents. Much of the time, food poisoning can be treated with home-care measures, but sometimes, medical intervention may be necessary. Read our definitive guide to food poisoning to learn how to diagnose, prevent, and treat food poisoning, wherever you happen to be on the globe.

Part I. Diagnosis and Treatment

Causes

It is important to understand the causes of food poisoning in order to gain an understanding of how to diagnose and treat the condition. Food may become contaminated anywhere in the production or preparation cycle, including farms, production plants, grocery stores, restaurants, and homes. Different types of food poisoning have different causes. Some common causes of food contamination that cause food poisoning are as follows:

• Meat comes into contact with the animal’s intestinal bacteria or feces and is not cooked long enough to kill those germs
• The water used to grow or prepare the food contains human or animal waste
• The person who prepared the food did not wash their hands beforehand
• The utensils, cutting surfaces, or other tools used to prepare the food are not clean
• Foods are not stored in the proper conditions or are left too long in temperatures at which microorganisms can thrive

Foods that are especially vulnerable to the above contaminations and that commonly cause food poisoning are as follows:

• Raw or undercooked fish, shellfish, meat, and eggs
• Unpasteurized dairy, fruit juice and vegetables (the process of pasteurizing prevents contamination)
• Foods containing mayonnaise (including potato salad and coleslaw) that are left out of the refrigerator too long
• Frozen or refrigerated foods that are left out of the refrigerator too long or are improperly reheated
• Home-canned foods or improperly canned commercial foods
• Smoked or salted fish
• Untreated drinking water, including well water and stream water

Common Symptoms

Food poisoning symptoms can range from mild or absent to severe; depending on the type and severity of the infection, you may have few or no symptoms, or you may experience life-threatening symptoms, such as severe dehydration or paralysis. Some common symptoms of food poisoning are as follows:

• Intestinal discomfort or cramps
• Nausea and vomiting
• Headache
• Fever and chills
• Watery diarrhea (may be bloody)
• Dizziness
• Weakness
• Dehydration

Symptom Checklist

Symptoms of some of the more common types of food poisoning are as follows. You are more likely to contract certain types of food poisoning when traveling in developing countries. Matching these symptoms against your own symptoms will help you and/or your doctor diagnose the type of food poisoning you are suffering from and determine a proper course of treatment.

Salmonella

• Fever
• Abdominal pain
• Diarrhea
• Nausea, and sometimes vomiting
• Symptoms appear 1 to 3 days after consuming the contaminated food
• You may have recently consumed meat, poultry, or egg yolks

E. Coli

• Severe, sometimes bloody diarrhea is the main symptom
• May also cause abdominal cramps, gas, fever, loss of appetite, or no symptoms
• Rare symptoms include vomiting, pale skin, bloody or reduced amount of urine, bruising to the skin
• Symptoms begin 1 to 8 days after consuming the contaminated food/water
• Most infections associated with eating undercooked ground beef; can also be caused by consuming unpasteurized milk or apple cider, alfalfa sprouts, other contaminated foods, or contaminated water

Shigella

• Nausea and vomiting
• Fever
• Abdominal cramps
• Bloody diarrhea
• Onset of symptoms is 24 to 48 hours
• You may have recently consumed seafood or raw, ready-to-eat produce

Campylobacter

• Diarrhea (may be bloody)
• Nausea and vomiting
• Abdominal pain and/or cramping
• Fever
• Malaise (general feeling of being unwell)
• Symptoms start after 2 to 5 days
• You may have recently consumed meat, poultry, unpasteurized milk or water from a questionable source

Listeria

• Diarrhea
• Nausea
• Fever
• Muscle aches
• Flu-like symptoms
• If the infection spreads to the spinal cord and brain, symptoms may include stiff neck, headache, confusion, loss of balance and convulsions
• You may be pregnant or elderly, take steroid medications, have a serious medical condition such as diabetes or kidney disease, or have a weakened immune system – these individuals are at a higher risk of contracting listeria than the general population
• You may have within the past day or two consumed soft cheeses (e.g., crumbled blue cheese, feta), cold cuts, lunch meat, hot dogs, unpasteurized milk, or raw, unwashed vegetables
• Symptoms start after 9 to 48 hours

Botulism

• Double vision
• Blurred vision
• Dry mouth
• Difficulty swallowing
• Muscle weakness
• Slurred or slowed speech
• Droopy eyelids
• If left untreated, more severe symptoms such as paralysis of legs, arms, trunk and respiratory muscles may occur
• Symptoms develop 18 to 36 hours after eating the contaminated food, but can occur as soon as six hours after or as late as 10 days later
• You have recently consumed canned foods, chili peppers, tomatoes, garlic chopped in oil, fermented fish (such as sardines), potatoes baked in aluminum foil, or another food that was kept at a warm temperature for too long
• In infants, symptoms may include constipation, lethargy, poor muscle tone, poor feeding habits and weak crying; consumption of honey may cause botulism in infants

Hepatitis A

• Muscle aches
• Loss of appetite
• Headache
• Fever
• Weakness
• Fatigue
• Abdominal discomfort
• Jaundice (after a few days)
• You may be staying in or have within the last month traveled to a developing country
• You may have in the last month consumed shellfish or raw produce or drunk water from a questionable source
• Symptoms do not present themselves until 28 days after the initial infection (typically)

Cholera

• A large amount of watery diarrhea (may have a “fishy” odor)
• Abdominal cramps
• Dry mouth and skin
• Excessive thirst
• Nausea and vomiting
• Low urine output
• Unusual sleepiness
• You may have recently consumed shellfish (especially raw oysters) or drinking water in a country where there is cholera – such as Africa, Asia, India, Mexico, or South or Central America

Fish tapeworm

• You have eaten raw or undercooked freshwater fish
• Symptoms may occur after several weeks, or you may not experience symptoms
• If symptoms do occur, they may include weight loss, weakness, diarrhea, abdominal pain/discomfort, B-12 deficiency, and/or visible segments of worm in the stool

When to See a Doctor

In most cases, food poisoning symptoms are relatively mild (e.g., a small amount of vomiting or diarrhea) and will resolve on their own with self-care after a few days. However, if symptoms are severe or you have certain medical situations, it is imperative that you call a doctor right away. See a doctor if any of the following is true:

• Your stools contain blood or pus
• You have a fever higher than 101°F, or your child has a fever higher than 100.4°F in addition to diarrhea
• You have signs of dehydration (dizziness, thirst, lightheadedness)
• You have diarrhea and cannot keep down liquids because of vomiting or nausea
• You have diarrhea after recently traveling to a foreign country
• You have food poisoning after eating fish or mushrooms
• You have symptoms of botulism
• Diarrhea does not resolve after 5 days (2 days in a child or infant) or gets worse with time
• You have noticed segments of worm in your stool
• The infected person is very young or old, is pregnant, or has another serious medical condition
• Your symptoms include a stiff neck or confusion

Food poisoning tests

To diagnose food poisoning, your doctor may, in some cases, simply consider your symptoms. The following tests may also be used to determine the infectious agent in your body that is causing your symptoms.

• Blood tests
• Stool culture test
• Inspection of stool for parasites
• Testing of the food that is potentially responsible for the poisoning

Medical treatments

 Medical treatments for food poisoning depend on the type and severity of the person’s condition and may include one or more the following:

• Intravenous rehydration
• Antibiotic treatment, such as tetracycline, cipro or doxycline
• Antitoxin medication
• Antiparasite medications, such as praziquantal or niclosamide
• Antinausea and/or antidiarrheal medication
• Enemas and/or induced vomiting
• Vitamin B-12 injections (for parasites causing B-12 deficiency)
• Hospitalization and intensive care (for severe illnesses, such as infant botulism)
• Liver transplant (for severe Hepatitis A infection)
• Poison antidotes, such as activated charcoal treatment

Alternative Diagnoses

In some cases, symptoms of another disease may mimic some common food poisoning symptoms, such as vomiting, diarrhea, abdominal pain, dizziness, and others. Some other conditions that cause certain food poisoning symptoms include the following:

• Gastroenteritis (the “stomach flu”)
• Lactose intolerance
• Pregnancy
• Severe anxiety
• Crohn’s disease
• Celiac disease
• Drug overdose
• Poisoning by another substance, e.g., carbon monoxide poisoning, poisoning from pesticides, household chemicals, or heavy metals

Part II. Prevention: At Home and Away

Food poisoning can generally be prevented if you take the proper precautions. Read on to find out the general food poisoning prevention precautions everyone should follow when preparing or consuming food, as well as special advice for preventing food poisoning if you’re traveling in a foreign country. There are also special precautions for people who are at a higher risk of contracting food poisoning because of their age or medical status.

Preventing food poisoning at home

Keep things clean

• Always wash hands before cooking and before eating. Also wash hands after touching raw meat. Hands should be washed for 20 seconds with soap and running water. Make sure to scrub between your fingers, under your nails, and the backs of your hands.
• Cleanse the surfaces and utensils used for cooking after each use. Rinsing with water is not enough. Use hot, soapy water to clean utensils and small cutting boards; use a bleach solution to clean countertops and larger cutting boards.
• Take special care to clean dishes and utensils that have contacted raw meat, fish, poultry, or eggs.
• Wash fruits and vegetables before preparing them (but not meat, poultry, or eggs). It is important to wash produce even if you plan to peel /cut it because bacteria can spread from the peel to the rest of the fruit/vegetable as you cut or peel it.

Avoid cross-contamination

• Keep prepared, ready-to-eat foods away from raw meat, poultry, fish, and eggs while you’re shopping at the grocery store or preparing the food, and in the refrigerator. For example, you should not put cooked meat back in the same container that held the food when it was raw.
• Use separate utensils, cutting boards, and plates for raw produce (fruits and vegetables) and for raw animal foods (meat, poultry, fish, and eggs).

Cook at the proper temperature

• Use a food thermometer when cooking to ensure that the food reaches its safe minimum cooking temperature. Internal temperatures for steak and roasts should reach at least 145°F, while ground beef should be cooked to at least 160°F. Cook poultry to at least 165°F, pork to at least 160°F, and fish to 145°F. Eggs should be cooked until the yolk is firm.
• Microwave frozen foods for the full amount of time instructed on the packaging (at 165°F or higher).
• If you plan to serve/consume the food shortly after cooking it, keep it at a temperature of at least 140°F after cooking it and during mealtime. The “danger zone” at which bacteria that cause food poisoning multiply in cooked foods is between 40°F and 140°F.
• If you can your own foods, make sure to follow proper canning temperatures and techniques to avoid botulism.

Keep things cold

• Refrigerate or freeze perishable food within two hours after cooking or purchasing it. In hot summer temperatures (90°F and above), refrigerate foods after one hour.
• Do not defrost food at room temperature. Thaw foods in the refrigerator, with the microwave (using the “defrost” or “50 percent power” setting) or by running cold water over it.
• Keep your refrigerator at 40°F or colder and your freezer at 0°F or colder.

Throw out old food

• Discard of meat, fish, or poultry that has been refrigerated uncooked for more than 1 or 2 days.
• Throw out perishable food that’s been sitting out at room temperature for too long (2 hours or longer).
• Consult this list of safe refrigerator/freezer storage times from FoodSafety.gov.

Use common sense

• Don’t cook with/eat foods whose expiration date has passed.
• Don’t cook with/eat foods that look or smell funny (even if they are not expired).
• Don’t cook with/eat packaged foods with a broken seal.
• Don’t cook with/eat canned food that is bulging or dented
• Don’t cook with/drink water from streams or well water if it has not been treated/chlorinated.

Preventing food poisoning when dining out

At parties and picnics

• Avoid party foods that are prone to causing food poisoning, especially if you notice they have been sitting out for awhile. Party foods that commonly cause food poisoning include deviled eggs, raw oysters, steak tartare, bread pudding, potato salad, coleslaw, and rare- or medium-cooked hamburger.
• Don’t eat food if you suspect or know the person who prepared it didn’t wash their hands or otherwise prepared it unsafely. If you don’t want to seem rude, make up an excuse as to why you can’t eat that food (e.g., you are full or you don’t like/are not in the mood for that particular type of food).

At restaurants

• Be selective about the establishments you dine at, paying attention to the cleanliness of the establishment and staff, as well as its ratings. Observe the parking lot and make sure the trash cans are not overflowing and that there is not pooled water around the restaurant. The bathroom should be clean and well kept, and staff should have clean uniforms and proper hair restraints. Also check restaurant reviews and make sure the establishment has a sanitation/food safety rating of “A.”
• Consider avoiding certain restaurant foods that are prone to causing food poisoning. These include salsa, guacamole (according to the CDC, salsa and guacamole are increasingly responsible for cases of restaurant food poisoning) and any food from a salad bar or buffet, which is likely to have been sitting out for a long time.
• Beware of “specials” at low-end restaurants – these are often used as a way to get rid of old meat.
• The Food Poison Journal warns restaurant-goers to avoid eating fish on a Monday, when it is likely to have been sitting in the refrigerator all weekend.
• Don’t be shy about sending back food that looks or smells strange or is lukewarm. Also be sure to send back meat or poultry that seems undercooked (is still pink in the middle).

Preventing food poisoning when traveling in developing countries

• See a doctor before traveling to a foreign country to get any medicines, immunizations, or advice that may be necessary to help you avoid food poisoning in the place(s) you are traveling to.
• Bring emergency rations on your trip when possible. Some energy bars or nuts can make for a decent meal replacement if no safe dining options are available.
• Bring water purification tablets if you are traveling to a region without water filtration systems (or if you’re not sure). These can be used to make tap water safe to drink.
• Pack alcohol-based sanitizer or hand wipes and wash or sanitize hands before you eat during your travels.
• Be highly selective about the establishments you dine at, consulting travel books and websites for recommendations of safe places to eat. Inspect the cleanliness of a restaurant before eating there.
• Don’t eat food from street vendors. Depending on the region and circumstances, they may not be subject to inspection and may therefore not be up to par with health standards.
• Avoid eating seafood, dairy products, and raw vegetables, which are more likely than other foods to contain harmful pathogens.
• Favor hot food that has been thoroughly cooked and raw foods that have peels (such as oranges or bananas).
• Drink only bottled or purified water, and do not drink any beverages containing ice (as the ice may have been made with unpurified tap water). Make sure seals on bottled water have not been broken.
• Eat small portions of a variety of foods. If you keep your portion size of any one food relatively small, you have a better chance of fighting off or minimizing any illness from that food in the event that it is contaminated.

Special precautions

Infants, young children, women who are pregnant or breastfeeding, elderly people, and people with weakened immune systems and/or chronic health conditions have greater risk of developing food poisoning than other people. Food poisoning may also be more severe and potentially life-threatening for these individuals. Avoid the following if you have an increased risk for developing food poisoning.

• Soft cheeses (like Brie, Camembert, or feta), unpasteurized cheeses, and blue-veined cheeses
• Meat spreads and pates
• Uncooked, cured meats (e.g., lunch meat, deli meat, uncooked hot dogs)
• Unpasteurized milk or milk products
• Unpasteurized juices or ciders
• Food that may contain raw or undercooked eggs, such as cookie dough or homemade ice cream
• Raw or undercooked meat/poultry
• Smoked, raw, or undercooked fish, especially shellfish (e.g., oysters, scallops, mussels, clams)
• Raw sprouts (e.g., bean, radish, alfalfa, radish)
• Honey (do not give to infants younger than 1 year; the risk does not pertain to older kids or adults)

Part III. If You Can’t Get to a Doctor

In some cases, you may come down with food poisoning but not be able to get to a doctor because you are somewhere where you cannot readily obtain medical help, such as a remote destination in a foreign country, or even on a plane. If you are in the United States and have food poisoning symptoms but are too sick to drive yourself to the doctor, call 9-1-1. Otherwise, note the following advice on how to take care of yourself when you have food poisoning.

In a foreign country

Rehydrate yourself. Rehydration is the most important first aid remedy for food poisoning. Sip bottled water or electrolyte drinks, such as Pedialyte or Gatorade. Drinking bottled water rather than tap water is especially important if you are a in a third-world/developing country. If possible, try to consume a recognized brand of bottled water, such as Perrier or Evian, rather than locally bottled water (which may contain the same contaminants as the local tap water). If you don’t have bottled water but are staying in a hotel, you can boil tap water using the coffeemaker. Of course, in a nicer hotel, you may be able to order bottled water from room service (or call for medical assistance, for that matter).

Check the CDC and U.S. Department of State websites. The CDC Travelers’ Health Website will have up-to-date information on disease outbreaks in your area and advice on what to do if you get sick in the particular country in which you are staying. On the U.S. Department of State’s USembassy.gov site, you can easily find the U.S. embassy and other emergency resources in your area.

Take medication if you absolutely need to. If you obtained an emergency antibiotic from your doctor before the trip, check your symptoms against those of the conditions the antibiotic is prescribed to treat. Many food poisoning cases will not be resolved with antibiotics, but an antibiotic may be used to treat food poisoning of a bacterial nature. Over-the-counter medications to stop diarrhea and vomiting are generally not recommended with food poisoning, because your body needs to rid itself of the toxins causing the food poisoning – and unfortunately, this elimination process could require more diarrhea and more vomiting. However, if you feel you need to take something to temporarily halt your symptoms so that you may get to the doctor, you may make the judgment call to take an antidiarrheal.

Before your trip: As noted in section I, you should make certain preparations before your trip, including a visit to your doctor to receive any pertinent medical advice, immunizations, etc. You might also consider buying international medical insurance before your trip. A quality plan will assist you in getting medical help anywhere in the world. Such plans may also reimburse or offset medical costs and/or the cost of missed flights and other travel arrangements in the event you get sick. Keep a copy of the policy, as well as your emergency medical information, with you at all times when traveling. Finally, always having cash and/or credit cards with you when traveling will help you get to and pay for a doctor when you have a medical emergency in a foreign country.

More first aid/home treatments for food poisoning are provided below.

On a plane

When you’re 30,000 feet in the air, your options for medical treatment are pretty limited. While this is a non-ideal time for food poisoning to creep on you, there are a few things you can do if you become ill on a plane:

–          Alert a flight attendant to your condition. He or she will help you out, monitoring your condition and bringing you fluids, an air-sickness bag, and anything else that might make you feel more comfortable. Normally, the FAA allows airplane passengers a 15-minute maximum of bathroom time before a flight attendant will knock to check on you. If you are sick, the flight attendant may bend this rule.

–          In addition to fluids, ask for pretzels or crackers. These bland foods might help settle your stomach, while the salt in them can help restore your electrolyte balance.

–          Once you land at the airport, rehydrate with electrolyte-infused beverages such as Gatorade and seek emergency medical assistance if necessary.

First aid/Home treatments

Wherever in the world you are when you get sick with food poisoning, you can reassure yourself with the fact that most food poisoning illnesses do not require medical treatment and will get better on their own with time (12 to 48 hours) and home care. In addition to getting plenty of rest, the following tips will help you recover faster and, in most cases, relieve your symptoms without medical assistance. If you have any of the symptoms or conditions mentioned in the “When to See a Doctor” section in Part I, seek immediate medical care.

To relieve diarrhea

• When choosing fluids, go for water, an electrolyte beverage, or other clear fluids, such as soup broth. Sodas and juices may be better than no fluids in an emergency, but they are usually acidic and sugary, which can sometimes worsen diarrhea. Aim to drink 8 to 10 glasses of clear fluid per day, including at least 1 cup every time you have diarrhea. Avoid caffeinated, alcoholic, or carbonated drinks.
• Once you are feeling up to eating, choose salty foods like pretzels and soup, and high-potassium foods like skinless potatoes and bananas. These foods will help restore your body’s electrolyte balance, which is disturbed when you lose a lot of fluids through diarrhea.
• More safe foods to eat as you begin to recover include refined white-flour bread products (such as pasta, white rice, Cream of Wheat, saltine crackers, or corn flakes), baked or broiled meat, and cooked vegetables like carrots, green beans, peeled zucchini, and mushrooms.
• Avoid dairy, greasy foods, spicy foods, and “gassy” vegetables like beans, broccoli, corn, and green, leafy vegetables.
• Eat many small meals a day instead of three big meals.

For nausea and vomiting

• The same rules regarding fluids for diarrhea apply (i.e., drink clear fluids), except you may have to be more careful about the quantity you consume at a time – quickly drinking an entire cup of fluid may trigger more vomiting. Try to sip drinks rather than guzzle them, even if you feel very thirsty.
• Once you are able to keep food down, eat bland foods such as English muffins, potatoes, rice, clear soups, and Jell-O. Low-fat dairy is also OK. As with diarrhea, you should be eating several small meals a day instead of three big meals.
• Sit up after you eat (don’t lie down).
• Avoid dairy, greasy foods, spicy foods, alcohol, and caffeine.
• To relieve a bad taste in your mouth after vomiting, suck on hard candies or rinse with a baking soda solution consisting of 1 tsp baking soda, ¾ tsp salt, and 4 cups warm water.

Emergency Resources

American Association of Poison Control Centers (for poison emergencies in the U.S.): 1-800-222-1222

CDC Travelers’ Health Website

U.S. embassy information

Report food poisoning