Food Poisoning

What is Food Poisoning

Food poisoning is an illness that is caused by eating or drinking contaminated foods or drinks. In most cases, food poisoning is mild and lasts 1–2 days.

However, some cases can be serious, especially for people who have weak body defense (immune) systems, older people, children and infants, and pregnant women.

What are the causes?

Foods can become contaminated with viruses, bacteria, parasites, mold, or chemicals as a result of:

• Poor personal hygiene, such as poor hand washing practices.
• Storing food improperly, such as not refrigerating raw meat.
• Using unclean surfaces for serving, preparing, and storing food.
• Cooking or eating with unclean utensils.

If contaminated food is eaten, viruses, bacteria, or parasites can harm the intestine. This often causes severe diarrhea. The most common causes of food poisoning include:

• Viruses, such as:
  • Norovirus.
  • Rotavirus.
• Bacteria, such as:
  • Salmonella.
  • Listeria.
  • E. coli(Escherichia coli).
• Parasites, such as:
  • Giardia.
  • Toxoplasmosis.

What are the signs or symptoms?

Symptoms may take several hours to appear after you consume contaminated food or drink. Symptoms include:

• Nausea.
• Vomiting.
• Cramping.
• Diarrhea.
• Fever and chills.
• Muscle aches.
• Dehydration. Dehydration can cause you to be tired and thirsty, have a dry mouth, and urinate less frequently.

How is this diagnosed?

Your health care provider can diagnose food poisoning with a medical history and physical exam. This will include asking you what you have recently eaten. You may also have tests, including:

• Blood tests.
• Stool tests.

How is this treated?

Treatment focuses on relieving your symptoms and making sure that you are hydrated. You may also be given medicines. In severe cases, hospitalization may be required and you may need to receive fluids through an IV tube.

Follow these instructions at home:

Eating and drinking

• Drink enough fluids to keep your urine clear or pale yellow. You may need to drink small amounts of clear liquids frequently.
• Avoid milk, caffeine, and alcohol.
• Ask your health care provider for specific rehydration instructions.
• Eat small, frequent meals rather than large meals.

Medicines

• Take over-the-counter and prescription medicines only as told by your health care provider. Ask your health care provider if you should continue to take any of your regular prescribed and over-the-counter medicines.
• If you were prescribed an antibiotic medicine, take it as told by your health care provider. Do notstop taking the antibiotic even if you start to feel better.

General instructions

• Wash your hands thoroughly before you prepare food and after you go to the bathroom (use the toilet). Make sure people who live with you also wash their hands often.
• Clean surfaces that you touch with a product that contains chlorine bleach.
• Keep all follow-up visits as told by your health care provider. This is important.

How is this prevented?

• Wash your hands, food preparation surfaces, and utensils thoroughly before and after you handle raw foods.
• Use separate food preparation surfaces and storage spaces for raw meat and for fruits and vegetables.
• Keep refrigerated foods colder than 40°F (5°C).
• Serve hot foods immediately or keep them heated above 140°F (60°C).
• Store dry foods in cool, dry spaces away from excess heat or moisture. Throw out any foods that do not smell right or are in cans that are bulging.
• Follow approved canning procedures.
• Heat canned foods thoroughly before you taste them.
• Drink bottled or sterile water when you travel.

Get help right away if:

Call 911 or go to the emergency room if:

• You have difficulty breathing, swallowing, talking, or moving.
• You develop blurred vision.
• You cannot eat or drink without vomiting.
• You faint.
• Your eyes turn yellow.
• Your vomiting or diarrhea is persistent.
• Abdominal pain develops, increases, or localizes in one small area.
• You have a fever.
• You have blood or mucus in your stools, or your stools look dark black and tarry.
• You have signs of dehydration, such as:
  • Dark urine, very little urine, or no urine.
  • Cracked lips.
  • Not making tears while crying.
  • Dry mouth.
  • Sunken eyes.
  • Sleepiness.
  • Weakness.
  • Dizziness.

Risk of Food Poisoning in Traveling

Food poisoning is an illness caused by organisms present in something you ate or drank. Some types of food poisoning trigger symptoms quickly. Others may take 1–2 weeks for symptoms to appear. Symptoms of food poisoning include:

• Diarrhea.
• Cramping.
• Fever.
• Vomiting.
• Dizziness.
• Aches and pains.

Before you travel, learn as much as you can about the foodborne illnesses that are common in the areas where you are going. The risk for food poisoning varies from country to country and from one region of the world to another.

Countries with a low risk include:

• The United States.
• Canada.
• Australia.
• New Zealand.
• Japan.
• Some countries in Europe.

Countries with a mid-range risk include:

• Countries in Eastern Europe.
• South Africa.
• Some Caribbean islands.

Countries with a high risk include:

• Countries in Asia.
• Countries in the Middle East.
• Countries in Africa.
• Mexico.
• Countries in Central and South America.

What types of illness can be passed through food and drinks?

Most cases of food poisoning are caused by bacteria or viruses, such as:

• E. coli.
• Campylobacteriosis.
• Shigellosis.
• Salmonellosis.
• Norovirus.
• Rotavirus.
• Astrovirus.

Food poisoning can also be caused by some microscopic parasites. These are organisms that live off of another larger organism. Illness caused by parasites can take 1–2 weeks to appear and may last several months. The illnesses include:

• Giardiasis.
• Amebiasis.
• Cyclosporiasis.
• Cryptosporidiosis.

Medicines are available to treat these infections.

How can I decrease my risk of food poisoning while traveling?

Good hand hygiene always helps protect your health. Carry small bottles of alcohol-based hand sanitizer. Use it to clean your hands before you eat. Also follow these basic guidelines for eating and drinking while traveling.

Foods that are generally safe to eat:

• Food that is thoroughly cooked.
• Food that is served hot.
• Hard-boiled eggs.
• Fruits and vegetables you wash and peel yourself.
• Milk or cheese that is treated with high heat (pasteurized).

Foods to avoid:

• Raw or undercooked foods.
• Raw or runny eggs.
• Food that is not hot (such as food that has been on a buffet or picnic table for a while).
• Raw fruits or vegetables that have not been washed and peeled.
• Other items made with fresh vegetables or fruits, like salad and salsa.
• Milk or cheese that is not pasteurized.
• Meat from local animals, such as monkeys and bats.

Drinks that are generally safe:

• Bottled waters, soda, or sports drinks.
• Drinks you know were sealed until you opened them.
• Water you know has been treated, boiled, or filtered to remove microorganisms.
• Ice from treated or bottled water.
• Drinks made with boiling water, such as tea or coffee.
• Pasteurized milk.

Drinks to avoid:

• Water from the tap or a well.
• Water from a fresh water source, such as a stream.
• Ice from a tap, well, or fresh water source.
• Beverages that include water from a well, tap, or fresh water source.
• Milk that is not pasteurized.
• Beverages from soda fountains.

What should I do if I think I have developed food poisoning while traveling?

• If you have been vomiting or have diarrhea, drink water or other fluids to replace what you lost.
• Take over-the-counter medicine to stop diarrhea. Consider packing a supply of antidiarrheal medicine to take with you.
• Contact your health care provider if your symptoms do not clear up after a few days.

How is food poisoning treated?

Most cases of food poisoning go away without treatment within 48 hours. Food poisoning caused by bacteria may be treated with antibiotic medicines. Viruses cannot be treated with antibiotics. Illnesses caused by parasites might respond to antiparasitic medicines. You can also treat symptoms of food poisoning with medicines to:

• Prevent or slow diarrhea (antidiarrheals).
• Rehydrate your body. Oral rehydration therapy (ORT) helps your body replace fluids and electrolytes lost in diarrhea or vomit.
• Treat rashes caused by diarrhea using hydrocortisone cream.

Should I be proactively treated for food poisoning before I travel?

Talk to your health care provider about your personal risk for contracting food poisoning while traveling. Discuss the foodborne illnesses that are common in the areas you plan to visit. Make sure you understand how to use any medicines your health care provider recommends. Some medicines can help prevent food poisoning. These include:

• Bismuth subsalicylate (BSS). This is an ingredient in over-the-counter antidiarrheal medicines. It might help some adult travelers prevent illness.
• Probiotics or “good” bacteria. Taking probiotics might help prevent some illnesses.
• Antibiotics. These protect against bacteria only. Taking antibiotics to prevent food poisoning is usually suggested only for people who have a compromised immune system.

How can I learn more?

• Visit a travel medicine clinic or speak with a health care provider who specializes in travel medicine as soon as you know your travel plans.
• Check the Travelers’ Health section on the website of the Centers for Disease Control and Prevention (CDC): http://wwwnc.cdc.gov/travel  

Food Poisoning from Marine Toxins

If you have food poisoning from marine toxins, you have gotten sick from eating fish or shellfish that contain poisons (toxins). This could be from eating mussels, oysters, clams, scallops, or other fish. The toxins occur naturally. The fish eat small organisms, including phytoplankton or algae, that produce toxins. The toxins stay in the fish and when you eat the fish, you eat the toxins, too. Bacteria can also grow in fish that are not kept cold enough before cooking.

What are some types of marine toxins and where are they found?

Scombroid Fish Poisoning

Scombroid fish poisoning is also called histamine fish poisoning or scombrotoxic fish poisoning. It occurs when you eat fish that has not been properly refrigerated or preserved. Certain types of fish naturally contain higher levels of the amino acid histidine. When these fish are not stored properly, bacteria can change histidine into histamines. These can make you sick. Types of fish more likely to cause scombroid fish poisoning include:

• Tuna.
• Mackerel.
• Bonito.
• Mahi mahi.
• Sardines.
• Anchovies.
• Herring.
• Bluefish.
• Amberjack.
• Marlin.

Scombroid fish poisoning can happen anywhere in the world.

Ciguatera Poisoning

You can get this illness from eating fish or moray eels contaminated with toxins from a certain type of algae (Gambierdiscus toxicus). It grows on coral reefs, and small reef fish eat it. Bigger reef fish then eat the smaller fish and ingest the toxins. You can get sick if you eat an infected reef fish or eel. This type of food poisoning comes from reef fish such as:

• Amberjack.
• Barracuda.
• Black grouper.
• Blackfin snapper.
• Cubera snapper.
• Red snapper.
• Greater amberjack.
• Hogfish.
• Horse-eye jack.
• King mackerel.
• Sea bass.
• Sturgeon.
• Yellow grouper.

Ciguatera poisoning usually happens in tropical and subtropical areas with warm water. But it can occur anywhere reef fish are eaten.

Paralytic Shellfish Poisoning

This type of shellfish poisoning is the most common and the most severe. Paralytic shellfish poisoning occurs most often in places where there are algal blooms. Algal blooms occur when large groups of harmful algae overgrow in the water. Shellfish caught in those waters can cause food poisoning. These include:

• Mussels.
• Clams.
• Crabs.
• Lobsters.

Symptoms range from headache, diarrhea, and vomiting to paralysis and difficulty breathing. Shellfish from the coastal waters of the Pacific states and New England are most likely to cause this type of food poisoning.

Neurotoxic Shellfish Poisoning

This type of shellfish poisoning affects the brain and nervous system. It also affects the stomach and digestive system. People who have asthma might have more severe or longer-lasting symptoms. Oysters, clams, and mussels from the coast of the southern United States and the Gulf of Mexico can cause this type of food poisoning.

How does marine toxin food poisoning happen?

Marine toxin food poisoning happens when fish or shellfish eat the algae that produce toxins and then you eat the contaminated fish or shellfish.

What are some common signs and symptoms of marine toxin food poisoning?

People often start feeling sick an hour or two after eating the fish or shellfish. Symptoms may last only a day or two. Symptoms depend on the type of marine toxin you ate. They may include:

• Nausea.
• Vomiting.
• Rash.
• Sweating.
• Swelling of the mouth.
• Changes in sensation, such as:
  • Numbness, tingling, or itchiness in your face, tongue, fingers, or toes.
  • Difficulty sensing heat or cold.
• Fatigue.
• Depression.
• Flu-like symptoms.
• Red or pink-looking (flushed) face.
• Headache.
• Racing heart.
• Itchiness.
• Difficulty seeing or blurriness.
• Difficulty breathing.
• Cramping.
• Diarrhea.
• Chills.
• Difficulty swallowing.
• Loss of coordination.
• Not being able to move (paralysis).

How is marine toxin food poisoning treated?

Treatment depends on the type of marine toxin:

• Medicines including antihistamines or epinephrine can be used to treat scombroid food poisoning.
• There is no treatment for ciguatera or shellfish food poisoning.

People with marine toxin food poisoning may also benefit from:

• Breathing support.
• Oral rehydration therapy (ORT) to replace fluids lost through vomiting and diarrhea.
• Over-the-counter medicines to relieve aches and pains.

How can I decrease my risk of marine toxin food poisoning?

• Do not eat shellfish:
  • If you have a weakened defense (immune) system or low immunity.
  • Caught after an algal bloom.
  • Sold as bait.
• Do not eat reef fish or moray eel.
• Pay attention to signs or public warnings that say it is not safe to fish in certain areas.
• Keep fish below 38°F (3.3°C) at all times before cooking.
• Do noteat the parts of fish where toxins concentrate. This includes the:
  • Liver.
  • Intestines.
  • Eggs (roe).
  • Head.
• Remember that some marine toxins can survive:
  • Cooking.
  • Canning.
  • Smoking.
  • Salting.
  • Pickling.
• Throw out fish that is old, has not been kept cold enough, or has spoiled or gone bad.
• Avoid eating shellfish while traveling abroad.