The Full Story
There are more than 250 types of food poisoning. It's no wonder that one in six Americans gets food poisoning every year
The causes of foodborne illness range from amebiasis and anthrax to vibrio and yersinia. They include bacteria, viruses, pesticides, natural toxins, molds, parasites, and more. But most people don't want an encyclopedia of food poisoning (though such things exist). They just don't want to get sick
Here are some Frequently Asked Questions about foodborne illness:
What foods cause the most cases of food poisoning?
The foods most often involved in cases of food poisoning are leafy vegetables, dairy, fruits and nuts, poultry, vegetables that grow on vines or stalks, beef, eggs, pork, grains and beans, and root vegetables.
The foods most often involved in food poisoning deaths are poultry, dairy, vegetables that grow on vines or stalks, fruits and nuts, leafy vegetables, pork, eggs, fish, and beef.
Who gets food poisoning?
Anyone who eats contaminated food is at risk. Food poisoning is especially dangerous for some groups of people, though:
- infants and young children;
- elderly people;
- people with chronic health conditions;
- people with a weak immune system, for example those with cancer, AIDS, diabetes, liver disease, or kidney disease.
What are the symptoms of food poisoning?
- Most types of food poisoning cause gastrointestinal (GI) symptoms. These include nausea/upset stomach, stomach cramps, vomiting, and diarrhea.
- One of the dangers of food poisoning is dehydration. Vomiting and diarrhea cause the body to lose a lot of fluid. If someone loses too much fluid, abnormal blood chemistry follows. This can cause weakness, tiredness, even an irregular heartbeat. Dehydration is especially serious for children and the elderly.
- Depending on the type of food poisoning, other symptoms are possible.
What are the most common causes of food poisoning?
Here are common causes of food poisoning in the US.
- Norovirus causes about 5.5 million illnesses every year.
- Found in many foods, including raw produce, contaminated drinking water, shellfish from contaminated water, and food contaminated by a food handler and then not reheated.
- Symptoms include nausea, vomiting (especially in children), diarrhea (especially in adults), fever, and headache.
- Symptoms begin about 12 - 48 hours after eating contaminated food and last for about 12 - 60 hours.
- Salmonella causes about 1 million illnesses every year. Salmonella is the leading cause of hospitalization and of death due to foodborne illness.
- Found in many foods, including unpasteurized milk or juice, cheese, eggs, poultry, contaminated raw produce, and peanut butter.
- Symptoms include fever and abdominal pain, vomiting, and diarrhea.
- Symptoms begin about 6 - 48 hours after eating contaminated food and last for about 4 -7 days.
- Clostridium perfringens causes about 970,000 illnesses every year.
- Found in meats, poultry, gravy, and other foods kept at room temperature too long.
- Symptoms include severe abdominal pain and watery diarrhea.
- Symptoms begin about 8 - 16 hours after eating contaminated food and last for about 24 hours.
- Campylobacter causes about 850,000 illnesses every year. It is most common in children under 5 years old.
- Found in poultry (raw or undercooked), unpasteurized milk, and contaminated water.
- Symptoms include fever, vomiting and diarrhea (which may be bloody), and abdominal cramps.
- Symptoms begin in 2 - 5 days and last from 2 - 10 days.
- Usually symptoms go away on their own, but some people develop arthritis or a neurological condition called Guillain-Barré syndrome.
- Streptococcus causes about 240,000 - 250,000 illnesses every year, although most of those aren't foodborne.
- Found in dairy products (milk, ice cream, cream, custard), eggs, potato salad, egg salad, shrimp salad, ground ham, and rice pudding. Illness is usually spread by food handlers and usually results from foods left at room temperature for too long.
- Symptoms include sore throat, pain while swallowing, fever, headache, nausea and vomiting, even a rash and symptoms of rheumatic fever. Symptoms are usually not severe in healthy people, but Streptococcus infections can be dangerous for elderly people or those with a major health condition.
- Symptoms usually begin in 1 - 3 days and begin to clear up in about four days. Onset and recovery are delayed for people who develop rheumatic fever.
- Streptococcus is one of a few foodborne illnesses for which antibiotics are used.
- Shigella causes about 130,000 illnesses every year. (Shigella is sometimes called “bacillary dysentery”.)
- Found in raw produce, uncooked foods, contaminated water, and cooked foods that are not reheated after being touched by an infected food handler.
- Symptoms include fever, stomach cramps, and diarrhea, which may contain blood or mucus.
- Symptoms begin in about 4 - 7 days and last about 1 - 2 days.
- E. coli (O157, non-O157, and other types) causes more than 200,000 illnesses every year.
- The most dangerous type is called hemorrhagic colitis (E. coli O157:H7).
- Sources include undercooked beef, especially ground beef; unpasteurized fruit juice, unpasteurized milk, raw fruits and vegetables (e.g. uncooked sprouts), and contaminated water.
- Symptoms include abdominal pain, vomiting, and severe diarrhea, which may be bloody. Kidney failure and death may occur, especially in young children.
- Symptoms begin in 1 - 8 days and last for 5 - 10 days. If kidney failure develops, recovery may take longer.
- “Travelers’ diarrhea” is caused by other types of E. coli.
- Sources include food or water that has been contaminated by human feces.
- Symptoms include stomach cramps and diarrhea, watery diarrhea, sometimes with vomiting.
- Symptoms begin in 1 - 3 days and last for 3 - 7 days.
- Yersinia enterocolitica causes nearly 100,000 illnesses every year.
- Sources include pork (including chitterlings) and other meats, unpasteurized milk, oysters, fish and crabs; also, infected food handlers.
- Symptoms include stomach pain, diarrhea, and high fever, sometimes with vomiting. Bloody diarrhea is possible.
- Symptoms begin in 24 hours, or as long as 2 weeks or more. They may resolve on their own within a few days to 3 weeks. Some people get joint pains and rashes which may take months to resolve.
- Toxoplasma gondii causes about 87,000 illnesses every year and is the second leading cause of death due to foodborne illness.
- Sources include undercooked contaminated meat, unwashed fruits and vegetables, and contaminated water. This parasite can sometimes be found in cat feces and soil; it is essential to wash hands after handling litter boxes or gardening.
- Symptoms include fever, headache, muscle aches, rash, and damage to the eyes or brain. Many people who are infected have no symptoms at all. Infected pregnant women can pass the illness to their children, who in rare cases may be born with brain or eye damage.
- In some cases, symptoms never occur. If they do, they may last for weeks. Illness can occur many years after exposure.
- Giardia intestinalis causes about 77,000 illnesses every year.
- Giardia is a parasite that lives in the intestinal tract of humans and animals. Sources include any food, water, or surfaces that contacted stool.
- Symptoms include stomach cramps, nausea, gas, and diarrhea. Some people have no symptoms.
- Symptoms usually begin in 1 - 3 weeks and last for 2 - 6 weeks.
- Cryptosporidium causes about 58,000 illnesses every year.
- Sources include contaminated water or food and food touched by an infected food handler.
- Symptoms include watery diarrhea, nausea and stomach cramps, and a low fever.
- Symptoms begin in 2 - 10 days and may last for weeks or months. Apparent recovery can be followed by a relapse.
- Bacillus cereus causes about 63,000 illnesses every year.
- Sources include meats, stews, rice products and starchy foods, milk, fish, and sauces.
- Symptoms include nausea, stomach cramps, and watery diarrhea.
- Symptoms begin within 10 - 16 hours and last for 24 - 48 hours.
Botulism is a rare but dangerous type of foodborne illness. Botulism is caused by bacteria, Clostridium botulinum. These bacteria produce spores. Botulism spores are found in soil, sediment in bodies of water, and in a number of animals. Under the right conditions, sealed off without oxygen, the spores then produce a toxin. Botulism toxin affects the nervous system.
In the US, there are about 145 reported cases of botulism each year. About 15 percent are foodborne botulism. About 65 percent are infant botulism. About 20 percent are wound botulism. (Wound botulism is not caused by eating contaminated food.)
Infant botulism and foodborne botulism have different sources, but effects and treatment are the same.
What about mushroom poisoning?
- Foodborne botulism usually is caused by improperly canned food. Most often, home canned food is involved, but sometimes it’s from a commercial source.
- Symptoms include muscle paralysis. Usually, it starts with droopy eyelids, blurred vision, double vision, dizziness, and weakness. As paralysis moves down the body, breathing muscles may be affected.
- Infant botulism is often caused by giving honey to children under 12 months of age.
- Early symptoms of infant botulism include constipation, poor feeding, a lot of drooling because of trouble swallowing, floppy muscles, and trouble breathing.
- Treatment of botulism includes helping the person breathe and giving antitoxin. About 10 - 15 percent of victims will die without treatment.
- When breathing muscles are paralyzed, a ventilator is needed. It may be needed for weeks to months.
- There is an antitoxin for botulism poisoning. It must be requested from the CDC, which will ship it to the treating hospital.
Some mushrooms are poisonous, even if they are not contaminated by bacteria, viruses, or parasites. Many kinds of wild mushrooms are poisonous to humans and to pets. Without special training, there is no reliable way to tell the safe ones from the harmful ones.
Do fish cause foodborne illness?
- Symptoms depend on the type of mushroom. Possible symptoms include nausea, vomiting, diarrhea, hallucinations, coma, kidney damage, liver damage, and death.
- Symptoms from the least dangerous poisonous mushrooms usually begin within minutes to a few hours. The most dangerous mushrooms don’t cause effects for at least several hours.
- For more information about wild mushrooms, read Wild Mushroom Warning, an article from The Poison Post®.
The puffer fish may be poisonous, even if it’s not spoiled by bacteria or viruses. Some fish and shellfish swallow toxins, so their flesh is poisonous to eat. Others cause illness because of spoilage, even though there are no clues that the fish is spoiled.
How does food become contaminated?
- Puffer fish, also known as blowfish or fugu: Parts of these fish contain a poison called tetrodotoxin. In some cases, the poison is found only in certain organs, for example the liver and skin. In others, tetrodotoxin is found in the meat itself. It takes an expert to tell which is which. Tetrodotoxin is also found in some frogs, newts, horseshoe crabs, starfish, and blue-ringed octopus (which inject the poison while biting). Very small amounts can be fatal.
- “Fugu” is considered a delicacy by some BUT the fish must be cut in just the right way. If not, poison can be transferred from the dangerous organs to the meat. The unsuspecting diner can be poisoned, even fatally. The only puffer fish that can be legally imported is the “tiger puffer”, Takifugu rubripes, from Japan. The fish must be cut by an expert.
- Symptoms begin with numbness of the lips and tongue, followed by nausea, vomiting, and trouble walking. Paralysis can follow, along with seizures, trouble breathing, and an irregular heartbeat. If the breathing muscles become paralyzed, the victim will die without a ventilator.
- Symptoms can begin in about 20 minutes. Death can occur within 20 minutes to 8 hours. If a victim survives for about 24 hours, he or she is likely to recover. There is no antidote for tetrodotoxin; victims are treated according to their symptoms.
- Ciguatoxin is formed by some kinds of dinoflagellates that live in warm waters. Small fish that eat these microorganisms are eaten by larger fish, those fish eaten by yet larger fish, and so on. The accumulated ciguatoxin in reef fish makes the flesh of the larger fish poisonous to people who eat them.
- Some of the fish that commonly contain ciguatoxin are barracuda, grouper, large snappers, and amberjack and other large jacks. These fish are found in warm water around the US, including southern Florida, the Bahamas, the Virgin Islands, Puerto Rico, and Hawaii.
- There are no clues to a fish with ciguatoxin. It will look, smell, and taste the same as a fish that’s not contaminated.
- There is no way to remove ciguatoxin from fish.
- The most unusual symptom is hot-cold reversal: hot things feel cold to the touch, cold things feel hot. Other symptoms include numbness and tingling, itching, muscle aches, headache, dizziness, and muscle weakness. Nausea, vomiting, and diarrhea may occur. Low blood pressure, high or low pulse rate, and an irregular heartbeat may also develop.
- Symptoms often begin within 6 hours and may last for weeks or months. Sometimes, symptoms last for years.
- Be sure to call Poison Control if you experience these symptoms a few hours after eating fish. Many doctors are not familiar with this kind of foodborne illness but the poison sepcialists are.
- Vibrio has become a common cause of foodborne illness in the U.S. Vibrio vulnificus is a bacterium that rarely causes illness but can be fatal if it does. Vibrio parahaemolyticus is a related bacterium that has much in common with Vibrio vulnificus. They are found in coastal areas, in warm salty water. Humans can be poisoned by eating fish or shellfish that eat Vibrio, or by drinking contaminated water. (Vibrio cholerae is a related but different bacterium that causes the illness cholera.)
- The most common sources are oysters, clams, and shrimp. (It is NOT true that eating oysters only in months with the letter “R” will prevent this illness!)
- Symptoms are gastrointestinal, including bloody diarrhea, vomiting, and cramping. Fever is common. In people with a compromised immune system, for example, people with cancer, AIDS, diabetes, or liver or kidney disease, the bacteria may enter the bloodstream and cause septicemia, a severe or fatal illness.
- Symptoms begin within hours to days. Victims with GI symptoms alone usually recover quickly. Victims who develop septicemia may die quickly.
- Scombroid fish poisoning looks like an allergic reaction. Some fish develop high levels of histamine if they’re not refrigerated properly. (Histamine is what causes other allergic symptoms, to pollen or foods, for example.) Histamine has no odor or taste, so the fish could taste normal.
- Sources commonly include tuna, bluefish, amberjack, marlin, and mahi mahi, among others. The problem occurs only when the fish are not refrigerated at any time from when they’re caught until they are prepared and served.
- Symptoms usually begin with a red, flushed face. A bad headache, itching, and blurred vision may follow, along with diarrhea and stomach cramps.
- Symptoms begin quickly, within a few minutes to an hour. Treatment is with antihistamines. Usually, the victim feels better within about 12 hours.
Food can become contaminated at many points from its origin to your table. Here are just a few:
- It might be contaminated from the beginning. For example, a chicken with infected reproductive organs can lay eggs containing salmonella. Fish feeding in contaminated water might have contaminated flesh. Vegetables irrigated with contaminated water, or grown near livestock, may have organisms on the surface.
- Pesticides or chemicals could somehow find their way into or onto food. Watermelons contaminated with the pesticide aldicarb sickened many people.
- Food could be washed or handled in a contaminated environment. Contaminated cantaloupe caused a recent outbreak of foodborne illness.
- Food could be processed in a contaminated facility. This was the case with the recent peanut butter recall.
- Proper processing techniques might not be used. For example, unpasteurized dairy products (raw milk, raw milk cheese) and fruit juices have caused illness. Meat processing plants must prevent organisms on animal hides from reaching the meat.
- Food handlers can contaminate food. This can happen if they are ill, if they don’t wash their hands often enough or after using the bathroom, or if they have a cut or sore on their hands.
- Foods might not be refrigerated properly. Fish left out after being caught is a cause of scombroid fish poisoning. Foods not kept hot enough can also cause illness. Foods left at room temperature for too long can make people sick. Families at home, groups at picnics, community suppers, banquets, and restaurants can all make this mistake.
- Cross-contamination of food can happen in home and restaurant kitchens. If the same knives and cutting boards are used for raw meat, poultry, or fish and vegetables, organisms can be transferred from one to the other.
How can I prevent food poisoning?
Remember: Clean, Separate, Cook, and Chill! No matter how complicated the topic, home cooks need to do just a few things to keep their food safe. FoodSafety.gov recommends four steps:
- Wash your hands, counters, cutting boards, knives, fruits, and vegetables.
- Don’t wash your meat, poultry, or eggs. You can splash bacteria around your kitchen.
- Separate your fruits and vegetables from meat, poultry, eggs, and seafood:
- When shopping, keep these items separate in your grocery cart and grocery bags. Use plastic bags for your raw meat, poultry, and seafood.
- Store these things separately in the refrigerator. Keep meats and poultry and fish from dripping on other foods.
- Use separate cutting boards, bowls, etc. for your raw meats, poultry, fish, and eggs. Use clean knives on your fruits and vegetables, too, especially if they will be served raw.
- Cook food until it’s safe. This is important whether you’re using the stove, oven, or microwave.
- A thermometer is your friend! Foodsafety.gov provides a chart to figure out safe internal temperatures.
- Keep cooked food hot enough. Food poisoning organisms grow best between 40⁰ and 140⁰ Fahrenheit.
- Chill food quickly after cooking.
- Put left-overs into the refrigerator within two hours.
- Food should be at room temperature for only one hour if the temperature is over 90⁰, for example at a picnic.
- Don’t thaw frozen foods on the counter. They will quickly be over 40⁰, in the danger zone for bacteria to grow.
These tips lead to a few other common-sense actions:
- Don’t eat raw eggs or dough containing raw eggs.
- Don’t use marinade from raw meat on cooked meat.
- Don’t put cooked meat back onto a plate that held raw meat - unless it’s been thoroughly washed.
And finally, remember that food doesn't last forever. If something’s been lurking in your fridge, do NOT taste it to see if it’s OK. Check your left-overs against the chart provided by foodsafety.gov.
How can I tell if I have food poisoning?
If more than one person gets sick after the same meal or event, food poisoning is a possibility. Otherwise, it can be hard to tell. Food poisoning can look like a lot of other illnesses, especially if the symptoms are mainly nausea, vomiting, and diarrhea.
A few foodborne illnesses have characteristic symptoms: an allergic-type reaction from scombroid fish poisoning, reversal of hot and cold sensations from ciguatera fish poisoning, and hallucinations from some types of wild mushrooms and from some weeds (Datura species) mistaken for greens.
What should I do if I get food poisoning?
At first, treatment will be fluids to prevent dehydration. If someone can’t hold fluids down - no matter why - call a health care provider. Sometimes, a trip to the emergency room for IV fluids will be needed.
If symptoms don’t go away on their own within a couple of days, call your health care provider. If food poisoning is possible, specific tests might be done. A few types of food poisoning, if confirmed by testing, can be treated with antibiotics. Otherwise, treatment is according to the symptoms the patient is having.
Should I report food poisoning?
You should report possible food poisoning. Public health officials want to figure out if other people are at risk of getting sick. They also want to prevent future episodes of foodborne illness.
- If you think you have gotten sick from eating a specific food or eating at a restaurant, call your county or city health department.
- For suspected problems with meat, poultry, or egg-based foods, call the USDA Meat and Poultry Hotline. Their number is 1-888-674-6854.
- For suspected problems with other foods, including eggs, call the FDA at 1-866-300-4374.
- For pet food, you can contact the FDA Consumer Complaint Coordinator. Find the number for your state at http://www.fda.gov/Safety/ReportaProblem/ConsumerComplaintCoordinators/.
What do food recalls mean?
A food recall means that a product is removed from sale. Sometimes, it means alerting consumers to check their own cabinets, refrigerators, or freezers for recalled food.
Food is recalled for a few reasons:
- The food might contain some type of organism that could make people sick.
- The food might be contaminated with a chemical or pesticide.
- The food might have been made or stored in unsanitary conditions. Examples include leaky roofs, unclean machinery, or rodents or insects in the facility.
- The ingredient label is incorrect. This can be dangerous for people with allergies, for example to dairy, wheat, soy, eggs, and nuts. If the label doesn’t match the ingredients, a product is called “mislabeled” or “misbranded”.
- Foreign objects might be in the food. Some examples include bits of plastic or small metal pieces; this can occur if a machine breaks down during processing.
- The facility wasn’t properly inspected or the food itself wasn’t properly inspected or tested.
Most food recalls happen when a company finds a problem with one of its products. Sometimes, people get sick and the FDA learns about it from health departments or the CDC. Or, FDA or USDA may uncover a problem while inspecting a facility.
The type of public notice depends on how serious the potential problem is. A major threat to public health involves contacting the media so that as many people as possible hear about it; updates are provided as needed. On the other hand, if a product is recalled before being sold, or if the recall is less serious, the recall may only be listed on a web site.
Where can I find out about food recalls?
- There are many possible causes of food poisoning: bacteria, viruses, pesticides, natural toxins, molds, parasites, and more.
- Food poisoning is especially dangerous for infants, young children, elderly people, those with chronic health conditions, and people with weak immune systems.
- Many types of food poisoning cause nausea, vomiting, diarrhea, and stomach pain. But, since there are so many types of food poisoning, there are many other possible symptoms.
- The most common types of food poisoning in the U.S. include norovirus, salmonella, clostridium perfringens, and campylobacter. The most dangerous types of food poisoning include E. coli and botulism.
- Some foods are poisonous. Examples include some kinds of mushrooms and certain kinds of fish (or their organs).
- Consumers can prevent much food poisoning by carefully handling the food that they buy, prepare, and serve.
- Someone with vomiting and diarrhea needs to drink plenty of fluids to stay hydrated. If that’s not possible, the person needs medical attention.
Rose Ann Gould Soloway, RN, BSN, MSEd, DABAT emerita
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