Food Poisoning

Definition

Food poisoning is a general term for health problems arising from eating contaminated food. Food may be contaminated by bacteria, viruses, environmental toxins, or toxins present within the food itself, such as the poisons in some mushrooms or certain seafood. Symptoms of food poisoning usually involve nausea, vomiting and/or diarrhea. Some food-borne toxins can affect the nervous system.

Description

Every year millions of people suffer from bouts of vomiting and diarrhea each year that they blame on "something I ate." These people are generally correct. Each year in the United States, one to two bouts of diarrheal illness occur in every adult. The Centers for Disease Control and Prevention (CDC) estimates that there are from six to 33 million cases of food poisoning in the United States annually. Many cases are mild and pass so rapidly that they are never diagnosed. Occasionally a severe outbreak creates a newsworthy public health hazard.

Classical food poisoning, sometimes incorrectly called ptomaine poisoning, is caused by a variety of different bacteria. The most common are Salmonella, Staphylococcus aureus, Escherichia coli O157:H7 or other E. coli strains, Shigella, and Clostridium botulinum. Each has a slightly different incubation period and duration, but all except C. botulinum cause inflammation of the intestines and diarrhea. Sometimes food poisoning is called bacterial gastroenteritis or infectious diarrhea. Food and water can also be contaminated by viruses (such as the Norwalk agent that causes diarrhea and the viruses of hepatitis A and E), environmental toxins (heavy metals), and poisons produced within the food itself (mushroom poisoning or fish and shellfish poisoning ).

Careless food handling during the trip from farm to table creates conditions for the growth of bacteria that make people sick. Vegetables that are eaten raw, such as lettuce, may be contaminated by bacteria in soil, water, and dust during washing and packing. Home canned and commercially canned food may be improperly processed at too low a temperature or for too short a time to kill the bacteria.

Raw meats carry many food-borne bacterial diseases. The United States Food and Drug Administration (FDA) estimates that 60% or more of raw poultry sold at retail carry some diseasecausing bacteria. Other raw meat products and eggs are contaminated to a lesser degree. Thorough cooking kills the bacteria and makes the food harmless. However, properly cooked food can become recontaminated if it comes in contact with plates, cutting boards, countertops, or utensils that were used with raw meat and not cleaned and sanitized.

Cooked foods can also be contaminated after cooking by bacteria carried by food handlers or from bacteria in the environment. It is estimated that 50% of healthy people have the bacteria Staphylococcus aureus in their nasal passages and throat, and on their skin and hair. Rubbing a runny nose, then touching food can introduce the bacteria into cooked food. Bacteria flourish at room temperature, and will rapidly grow into quantities capable of making people sick. To prevent this growth, food must be kept hot or cold, but never just warm.

ALICE CATHERINE EVANS (1881–1975)

Alice Catherine Evans was born on January 29, 1881, in Neath, Pennsylvania. Evans was the second of two children born to Anne Evans and William Howell. Evans taught grade school for four years because she could not afford to pay college tuition. Following her time as a teacher, Evans enrolled at the Cornell University College of Agriculture, earning her B.S. degree. Evans' professor recommended her for a scholarship, which she received, and she began her master's degree program at the University of Wisconsin where she earned her degree in 1910.

In 1911, Evans took a position with the University of Wisconsin's Dairy Division as a researcher studying cheese-making instead of continuing her education. In 1913, she moved to Washington, D.C., with the division and worked with a team on identifying the cause of contamination in raw cow's milk. By 1917, Evans' research had shown that the bacteria responsible for undulant (Malta) fever was very similar to one found when a cow experienced a spontaneous abortion. When administered to guinea pigs, the two bacteria produced similar results. Her findings were met with much skepticism but, as time went on, Evans' research began to gain support. She continued to document cases of the disease and to argue for the pasteurization process. Finally, after 1930, officials responsible for public health and safety realized the need for this process, which ultimately became a standard procedure. Evans retired from her position with the National Institute of Health in 1945 and died on September 5, 1975.

Although the food supply in the United States is probably the safest in the world, anyone can get food poisoning. Serious outbreaks are rare. When they occur, the very young, the very old, and those with immune system weaknesses have the most severe and life-threatening cases. For example, this group is 20 times more likely to become infected with the Salmonella bacteria than the general population.

Travel outside the United States to countries where less attention is paid to sanitation, water purification, and good food handling practices increases the chances that a person will get food poisoning. People living in institutions such as nursing homes are also more likely to get food poisoning.

Causes and symptoms

The symptoms of food poisoning occur because food-borne bacteria release toxins or poisons as a byproduct of their growth in the body. These toxins (except those from C. botulinum ) cause inflammation and swelling of the stomach, small intestine and/or large intestine. The result is abdominal muscle cramping, vomiting, diarrhea, fever, and the chance of dehydration. The severity of symptoms depends on the type of bacteria, the amount consumed, and the individual's general health and sensitivity to the bacterial toxin.

Salmonella

According to a 2001 report from the CDC, Salmonella caused almost 50,000 culture-confirmed cases of food poisoning in the United States annually. However, between two and four million probably occur each year. Salmonella is found in egg yolks from infected chickens, in raw and undercooked poultry and in other meats, dairy products, fish, shrimp, and many more foods. The CDC estimates that one out of every 50 consumers is exposed to a contaminated egg yolk each year. However, thorough cooking kills the bacteria and makes the food harmless. Salmonella is also found in the feces of pet reptiles such as turtles, lizards, and snakes.

About one out of every 1,000 people get food poisoning from Salmonella. Of these, two-thirds are under age 20, with the majority under age nine. Most cases occur in the warm months between July and October.

Symptoms of food poisoning begin eight to 72 hours after eating food contaminated with Salmonella. These include traditional food poisoning symptoms of abdominal pain, diarrhea, vomiting, and fever. The symptoms generally last one to five days. Dehydration can be a complication in severe cases. People generally recover without antibiotic treatment, although they may feel tired for a week after the active symptoms subside.

Staphylococcus aureus

Staphylococcus aureus is found on humans and in the environment in dust, air, and sewage. The bacteria is spread primarily by food handlers using poor sanitary practices. Almost any food can be contaminated, but salad dressings, milk products, cream pastries, and any food kept at room temperature, rather than hot or cold are likely candidates.

It is difficult to estimate the number of cases of food poisoning from Staphylococcus aureus that occur each year, because its symptoms are so similar to those caused by other foodborne bacteria. Many cases are mild and the victim never sees a doctor.

Symptoms appear rapidly, usually one to six hours after the contaminated food is eaten. The acute symptoms of vomiting and severe abdominal cramps without fever usually last only three to six hours and rarely more than 24 hours. Most people recover without medical assistance. Deaths are rare.

Escherichia coli (E. coli)

There are many strains of E. coli, and not all of them are harmful. The strain that causes most severe food poisoning is E. coli O157:H7. Food poisoning by E. coli occurs in three out of every 10,000 people. Foodborne E. coli is found and transmitted mainly in food derived from cows such as raw milk, raw or rare ground beef and fruit or vegetables that are contaminated.

Symptoms of food poisoning from E. coli are slower to appear than those caused by some of the other foodborne bacteria. E. coli produces toxins in the large intestine rather than higher up in the digestive system. This accounts for the delay in symptoms and the fact that vomiting rarely occurs in E. coli food poisoning.

One to three days after eating contaminated food, the victim with E. coli O157:H7 begins to have severe abdominal cramps and watery diarrhea that usually becomes bloody within 24 hours. There is little or no fever, and rarely does the victim vomit. The bloody, watery diarrhea lasts from one to eight days in uncomplicated cases.

Campylobacter jejuni (C. jejuni)

According to the FDA, C. jejuni is the leading cause of bacterial diarrhea in the United States. It is responsible for more cases of bacterial diarrhea than Shigella and Salmonella combined. Anyone can get food poisoning from C. jejuni, but children under five and young adults between the ages of 15 and 29 are more frequently infected.

C. jejuni is carried by healthy cattle, chickens, birds, and flies. It is not carried by healthy people in the United States or Europe. The bacteria is also found ponds and stream water. The ingestion of only a few hundred C. jejuni bacteria can make a person sick.

Symptoms of food poisoning begin two to five days after eating food contaminated with C. jejuni. These symptoms include fever, abdominal pain, nausea, headache, muscle pain, and diarrhea. The diarrhea can be watery or sticky and may contain blood. Symptoms last from seven to 10 days, and relapses occur in about one quarter of people who are infected. Dehydration is a common complication. Other complications such as arthritis-like joint pain and hemolytic-uremic syndrome (HUS) are rare.

Shigella

Shigella is a common cause of diarrhea in travelers to developing countries. It is associated with contaminated food and water, crowded living conditions, and poor sanitation. The bacterial toxins affect the small intestine.

Symptoms of food poisoning by Shigella appear 36-72 hours after eating contaminated food. These symptoms are slightly different from those associated with most foodborne bacteria. In addition to the familiar watery diarrhea, nausea, vomiting, abdominal cramps, chills and fever occur. The diarrhea may be quite severe with cramps progressing to classical dysentery. Up to 40% of children with severe infections show neurological symptoms. These include seizures caused by fever, confusion, headache, lethargy, and a stiff neck that resembles meningitis.

The disease runs its course usually in two to three days but may last longer. Dehydration is a common complication. Most people recover on their own, although they may feel exhausted, but children who are malnourished or have weakened immune systems may die.

Clostridium botulinum (C. botulinum)

C. botulinum, which causes both adult botulism and infant botulism, is unlike any of the other foodborne bacteria. First, C. botulinum is an anaerobic bacterium in that it can only live in the absence of oxygen. Second, the toxins from C. botulinum are neurotoxins. They poison the nervous system, causing paralysis without the vomiting and diarrhea associated with other foodborne illnesses. Third, toxins that cause adult botulism are released when the bacteria grows in an airless environment outside the body. They can be broken down and made harmless by heat. Finally, botulism is much more likely to be fatal even in tiny quantities.

Adult botulism outbreaks are usually associated with home canned food, although occasionally commercially canned or vacuum packed foods are responsible for the disease. C. botulinum grows well in non-acidic, oxygen-free environments. If food is canned at too low heat or for too brief a time, the bacteria is not killed. It reproduces inside the can or jar, releasing its deadly neurotoxin. The toxin can be made harmless by heating the contaminated food to boiling for ten minutes. However, even a very small amount of the C. botulinum toxin can cause serious illness or death.

Symptoms of adult botulism appear about 18-36 hours after the contaminated food is eaten, although there are documented times of onset ranging from four hours to eight days. Initially a person suffering from botulism feels weakness and dizziness followed by double vision. Symptoms progress to difficulty speaking and swallowing. Paralysis moves down the body, and when the respiratory muscles are paralyzed, death results from asphyxiation. People who show any signs of botulism poisoning must receive immediate emergency medical care to increase their chance of survival.

Infant botulism is a form of botulism first recognized in 1976. It differs from food-borne botulism in its causes and symptoms. Infant botulism occurs when a child under the age of one year ingests the spores of C. botulinum. These spores are found in soil, but a more common source of spores is honey.

The C. botulinum spores lodge in the baby's intestinal tract and begin to grow, producing their neurotoxin. Onset of symptoms is gradual. Initially the baby is constipated. This is followed by poor feeding, lethargy, weakness, drooling, and a distinctive wailing cry. Eventually, the baby loses the ability to control its head muscles. From there the paralysis progresses to the rest of the body.

Diagnosis

One important aspect of diagnosing food poisoning is for doctors to determine if a number of people have eaten the same food and show the same symptoms of illness. When this happens, food poisoning is strongly suspected. The diagnosis is confirmed when the suspected bacteria is found in a stool culture or a fecal smear from the person. Other laboratory tests are used to isolate bacteria from a sample of the contaminated food. Botulism is usually diagnosed from its distinctive neurological symptoms, since rapid treatment is essential. Many cases of food poisoning go undiagnosed, since a definite diagnosis is not necessary to effectively treat the symptoms. Because it takes time for symptoms to develop, it is not necessarily the most recent food one has eaten that is the cause of the symptoms.

Treatment

Treatment of food poisoning, except that caused by C. botulinum, focuses on preventing dehydration by replacing fluids and electrolytes lost through vomiting and diarrhea. Electrolytes are salts and minerals that form electrically charges particles (ions) in body fluids. Electrolytes are important because they control body fluid balance and are important for all major body reactions. Pharmacists can recommend effective, pleasant-tasting, electrolytically balanced replacement fluids that are available without a prescription. When more fluids are being lost than can be consumed, dehydration may occur. Dehydration more likely to happen in the very young, the elderly, and people who are taking diuretics. To prevent dehydration, a doctor may give fluids intravenously.

In very serious cases of food poisoning, medications may be given to stop abdominal cramping and vomiting. Anti-diarrheal medications are not usually given. Stopping the diarrhea keeps the toxins in the body longer and may prolong the infection.

People with food poisoning should modify their diet. During period of active vomiting and diarrhea they should not try to eat and should drink only clear liquids frequently but in small quantities. Once active symptoms stop, they should eat bland, soft, easy to digest foods for two to three days. One example is the BRAT diet of bananas, rice, applesauce, and toast, all of which are easy to digest. Milk products, spicy food, alcohol and fresh fruit should be avoided for a few days, although babies should continue to breastfeed. These modifications are often all the treatment that is necessary.

Severe bacterial food poisonings are sometimes treated with antibiotics. Trimethoprim and sulfamethoxazole (Septra, Bactrim), ampicillin (Amcill, Polycill) or ciprofloxacin (Ciloxan, Cipro) are most frequently used.

Botulism is treated in a different way from other bacterial food poisonings. Botulism antitoxin is given to adults, but not infants, if it can be administered within 72 hours after symptoms are first observed. If given later, it provides no benefit.

Both infants and adults require hospitalization, often in the intensive care unit. If the ability to breathe is impaired, patients are put on a mechanical ventilator to assist their breathing and are fed intravenously until the paralysis passes.

Alternative treatment

Alternative practitioners offer the same advice as traditional practitioners concerning diet modification. In addition they recommend taking charcoal tablets, Lactobacillus acidophilus, Lactobacillus bulgaricus, and citrus seed extract. An electrolyte replacement fluid can be made at home by adding one teaspoon of salt and four teaspoons of sugar to one quart of water. For food poisoning other than botulism, two homeopathic remedies, either Arsenicum album or Nux vomica, are strongly recommended.

Prognosis

Most cases of food poisoning (except botulism) clear up on their own within one week without medical assistance. The ill person may continue feel tired for a few days after active symptoms stop. So long as the ill person does not become dehydrated, there are few complications. Deaths are rare and usually occur in the very young, the very old and people whose immune systems are already weakened.

Complications of Salmonella food poisoning include arthritis-like symptoms that occur three to four weeks after infection. Although deaths from Salmonella are rare, they do occur. Most deaths caused by Salmonella food poisoning have occurred in elderly people in nursing homes.

Adults usually recover without medical intervention, but many children need to be hospitalized as the result of E. coli food poisoning. E. coli toxins may be absorbed into the blood stream where they destroy red blood cells and platelets. Platelets are important in blood clotting. About 5% of victims develop hemolytic-uremic syndrome which results in sudden kidney failure and makes dialysis necessary. (Dialysis is a medical procedure used to filter the body's waste product when the kidneys have failed).

Botulism is the deadliest of the bacterial foodborne illnesses. With prompt medical care, the death rate is less than 10%.

Prevention

Food poisoning is almost entirely preventable by practicing good sanitation and good food handling techniques. These include:

• keep hot foods hot and cold foods cold
• cook meat to the recommended internal temperature, use a meat thermometer to check and cook eggs until they are no longer runny
• refrigerate leftovers promptly, do not let food stand at room temperature
• avoid contaminating surfaces and other foods with the juices of uncooked meats
• wash fruits and vegetables before using
• purchase pasteurized dairy products and fruit juices
• throw away bulging or leaking cans or any food that smells spoiled
• wash hands well before and during food preparation and after using the bathroom
• sanitize food preparation surfaces regularly

Resources

OTHER

U. S. Food and Drug Administration. Center for Food Safety and Applied Nutrition. Bad Bug Book. 〈http://vm.cfsan.fda.gov〉.

KEY TERMS

Diuretic— Medication that increases the urine output of the body.

Electrolytes— Salts and minerals that produce electrically charged particles (ions) in body fluids. Common human electrolytes are sodium chloride, potassium, calcium, and sodium bicarbonate. Electrolytes control the fluid balance of the body and are important in muscle contraction, energy generation, and almost all major biochemical reactions in the body.

Lactobacillus acidophilus — This bacteria is found in yogurt and changes the balance of the bacteria in the intestine in a beneficial way.

Platelets— Blood cells that help the blood to clot.

Food poisoning

Definition

Food poisoning is a general term for health problems arising from eating food contaminated by viruses, chemicals, or bacterial toxins. Types of food poisoning include bacterial food poisoning, shellfish poisoning, and mushroom poisoning. The medical term for food poisoning is gastroenteritis .

Description

The Centers for Disease Control and Prevention (CDC) estimates that there are up to 33 million cases of food poisoning in the United States each year. Many cases are mild, and they pass so rapidly that they are never diagnosed. Occasionally, a severe outbreak creates a newsworthy public health hazard, but these instances are rare. Anyone can get food poisoning, but the very young, the very old, and those with compromised immune systems have the most severe and life-threatening cases.

Causes & symptoms

General indications of food poisoning include diarrhea, stomach pain or cramps, gurgling sounds in the stomach, fever, nausea , and vomiting . Dehydration is a common complication, since fluids and electrolytes are lost through vomiting and diarrhea. Dehydration is more

likely to happen in the very young, the elderly, and people who are taking diuretics.

Bacterial sources of food poisoning

Bacteria are major causes of food poisoning. Symptoms of bacterial food poisoning occur because foodborne bacteria release enterotoxins, or poisons, as a byproduct of their growth in the body. These toxins often diminish the absorptive ability of the intestines and cause the secretion of water and electrolytes that leads to dehydration. The severity of symptoms depends on the type of bacteria, the amount of bacteria and food consumed, and the individual's health and sensitivity to the bacteria's toxin.

SALMONELLA. Symptoms of poisoning begin 12–72 hours after eating food contaminated with Salmonella. Classic food poisoning symptoms, including fever, occur for about two to five days. Salmonella is usually transmitted through the consumption of food contaminated by human or other animal feces. This contamination is mostly due to lack of hand washing by food handlers.

ESCHERICHIA COLI (E. COLI ). Symptoms of food poisoning from E. coli 0157:H7 and similar strains of E. coli are slower to appear than those caused by some of the other foodborne bacteria. One to three days after eating contaminated food, the victim begins to have severe abdominal cramps and watery diarrhea that usually becomes bloody. The diarrhea may consist mostly of blood and very little stool, so the condition is sometimes called hemorrhagic colitis. There is little or no fever, the bloody diarrhea lasts from one to eight days, and the condition usually resolves by itself. Food contamination from E. coli O157:H7 has mostly been found in raw or undercooked ground beef. Raw milk has also been a source of food poisoning by E. coli.

CAMPYLOBACTER JEJUNI. C. jejuni infections are most often caused by contaminated chicken, but unchlorinated water and raw milk may also be sources of infection. Classic symptoms of food poisoning, including fever and diarrhea, begin two to five days after consuming food or water contaminated with C. jejuni. The diarrhea may be watery and may contain blood. Symptoms last from seven to 10 days, and relapses occur in about one quarter of the people who are infected.

STAPHYLOCOCCUS AUREUS (STAPH). Staph is spread primarily by food handlers with Staph infections on their skin. However, contaminated equipment and food preparation surfaces may also be at fault. Almost any food can be contaminated, but salad dressings, milk products, cream pastries, and food kept at room temperature, rather than hot or cold, are likely candidates. Classic symptoms of food poisoning appear rapidly, usually two to eight hours after the contaminated food is eaten. Such symptoms usually last only three to six hours and rarely more than two days. Most cases are mild and the victim recovers without any assistance.

SHIGELLA. Symptoms of food poisoning by Shigella appear 36–72 hours after eating contaminated food. These symptoms are slightly different from those associated with most foodborne bacteria. In addition to the familiar symptoms of food poisoning, up to 40% of children with severe infections show neurological symptoms. These include seizures, confusion, headache , lethargy, and a stiff, sore neck. The disease runs its course in two to three days.

CLOSTRIDIUM BOTULINUM. C. botulinum (commonly known as botulism) is the deadliest of the bacterial foodborne illnesses. Sources for adult botulism are

often improperly canned or preserved food. Symptoms of adult botulism appear about 18 to 36 hours after the contaminated food is eaten, although there are documented times of onset ranging from four hours to eight days. Unlike other foodborne illnesses, there is no vomiting and diarrhea associated with botulism. Initially, a person suffering from botulism feels weakness, dizziness , and double vision. Symptoms progress to difficulty with speaking and swallowing. The toxins from C. botulinum are neurotoxins—they poison the nervous system, causing paralysis. If the disease proceeds unchecked, paralysis will move throughout the body. Eventually, without medical intervention, the respiratory muscles will become paralyzed and the victim will suffocate.

With infant botulism, the spores of C. botulinum lodge in the infant's intestinal tract. Honey, especially when consumed by infants younger than 12 months, is sometimes the source of these spores. Onset of the symptoms is gradual. The infant initially has constipation , followed by poor feeding, lethargy, weakness, drooling, and a distinctive wailing cry. Eventually the baby loses the ability to control its head muscles. Paralysis then progresses to the rest of the body.

Fish-associated food poisoning

Ciguatera fish poisoning is caused by toxins accumulated in the tissues of certain tropical fish, including groupers, barracudas, snappers, and mackerel. Signs of poisoning occur about six hours after eating the fish. Around the mouth, there may be numbness and tingling, which may spread to other places including the hands and feet. There is often muscle pain and weakness, headache, dizziness, joint pain, sensitivity to temperature, heart arrhythmias, dramatic changes in heart rate, and reduced blood pressure. Reef fish contaminated with ciguatoxin are being exported all over the world, occurrence of ciguatera is becoming more likely in colder climates.

Pufferfish, or fugu, is a traditional gourmet dish served mostly in Japan. The skin and other organs of the pufferfish contain a strong poison called tetradotoxin. The first stage of tetradotoxin poisoning is indicated by numbness of the lips and tongue, which may occur 20–180 minutes after eating the fish. This is followed by tingling and numbness of the face, hands, and feet. Classic symptoms of food poisoning are accompanied by other neurological symptoms such as light-headedness, headache, and unsteady gait. The second stage of tetradotoxin poisoning brings on a progressive paralysis. Breathing, talking, and other movement becomes difficult. Cyanosis (bluish or purplish skin discoloration), low blood pressure, and arrhythmias may occur. Convulsions and mental impairment may happen right before death, or the person may be completely lucid, though unmoving. Death usually occurs four to six hours after ingestion of the fish if there is no proper intervention; that time, however, has been known to be as little as 20 minutes.

Shellfish poisoning is caused by toxins made by certain algae eaten by shellfish. The toxins are then accumulated in the bodies of the shellfish. Cockles, mussels, clams, oysters, and scallops are most often affected. Sometimes the toxin-producing algae multiply to such an extent that they cause the waters they live in to take on the reddish color of their bodies. This phenomenon is known as a red tide. Warnings are often given against eating shellfish from such areas. Symptoms of food poisoning show up within a half an hour to two hours of eating the

shellfish, depending on the amount and type eaten. There may be burning and tingling in the face and mouth, numbness, drowsiness, muscular pain, dizziness, diarrhea, stomachache, confusion, nausea, vomiting, odd temperature sensations, difficulty breathing, and possibly coma. The symptoms may last from a few hours to a few days.

Histamine poisoning can occur from eating fish whose body tissues have begun to produce high levels of histamine. Mackerel, tuna, and mahi mahi are most often the sources. After consumption of the fish, immediate facial flushing and hives may occur, as well as classic symptoms of food poisoning becoming evident a few minutes later. Symptoms usually last less than 24 hours.

Mushroom poisoning

Mushroom poisoning is classified by the effects of the poisons. Protoplasmic poisons result in cell destruction, often in the liver, which progresses to complete organ failure. Neurotoxins cause neurological symptoms such as sweating, convulsions, hallucinations, excitement, depression , coma, and colon spasms. Gastrointestinal (G/I) irritants rapidly bring on the classic symptoms of food poisoning and then resolve just as quickly. Disulfiram-like poisons are generally nontoxic, except when alcohol is consumed within 72 hours of eating them. In these cases, the poisons cause headache, nausea, vomiting, flushing, and cardiac disturbances for two to three hours.

Other possible sources

Other possible sources of food poisoning include ingestion of green or sprouting raw potatoes, ingestion of fava beans by susceptible persons, and ergot poisoning from ingestion of contaminated grain. Chemical contaminant food poisoning may result from the ingestion of unwashed produce sprayed with arsenic, lead, or insecticides. Food served or stored in lead-glazed pottery cadmium-lined containers may also lead to food poisoning.

Diagnosis

An important aspect of diagnosing food poisoning is the clinical interview. A history of the illness should be thoroughly traced to include ingestion of food, recent travel, and contact with those showing similar symptoms of illness. Because it may take 30 minutes to three days for symptoms to develop, it is not necessarily the most recent food eaten that is the cause of the symptoms. Diagnosis is confirmed with a stool culture. Other laboratory tests may be used to examine vomitus, blood, or the contaminated food. A blood chemistry panel may be performed to determine the extent of any tissue damage or electrolyte imbalances. Many cases of food poisoning go undiagnosed, and treatment focuses on the short-lived G/I symptoms.

Botulism is usually diagnosed from its distinctive neurological symptoms, since rapid treatment is essential to save the patient's life. Electromyography, a test analyzing the electrical activity of muscles, may later be done to further confirm diagnosis. The test shows abnormal muscle activity in most cases of botulism.

Treatment

Those suffering from food poisoning should reduce all sugar and normal food for eight to 24 hours, and increase fluids to avoid dehydration. Charcoal tablets, Lactobacillus acidophilus, Lactobacillus bulgaricus, and citrus seed extract are all recommended. For mild cases of food poisoning, the homeopathic remedies Arsenicum album, Veratrum album, Podophyllum, or Nux vomica are recommended. The remedy should be given in 12c potency every three to four hours until symptoms subside. If a ready-made electrolyte replacement is not available, a homemade one can be made by dissolving exactly 1 tsp (5 ml) of salt and 4 tsp (20 ml) of sugar in 1 qt (1 l) of water.

Cinnamon (Cinnamonum zeylanicum), cloves (Syzigium aromaticum), oregano (Origanum vulgare ), and sage (Salvia officinalis ) are food herbs that are also strong inhibitors of bacteria. Liberal amounts can be added to foods, especially when traveling. Grapefruit seed extract has a natural antibiotic effect and may be of help. Large amounts of garlic , in food and in supplement form, are also recommended for the same reason.

Allopathic treatment

In serious cases of food poisoning, medications may be given to stop abdominal cramping and vomiting. Medications are not usually given for the diarrhea, since stopping it might keep toxins in the body longer and prolong the illness. Severe bacterial food poisonings are sometimes treated with antibiotics, but their use is controversial. Washing out the stomach contents to remove the toxic substances may be required. This procedure is called gastric lavage, familiarly known as having the stomach pumped. Neurotoxins often interfere with the breathing process. If the ability to breathe is affected, patients may have to be put on a mechanical ventilator to assist their breathing and are fed intravenously until the paralysis passes.

People who show any signs of botulism poisoning must receive immediate emergency medical care. Both infants and adults suffering from food poisoning by C. botulinum require hospitalization, often in the intensive care unit. A botulism antitoxin is given to adults, if it can be administered within 72 hours after symptoms are first observed. If given later, it provides no benefit. Nasogastric intubation is recommended for the feeding of infants with active botulism. As well as supplying nutrition , it will stimulate peristalsis, helping in the elimination of C. botulinum.

Treatment of food poisoning that is usually not an emergency situation may include drugs such as ipecac syrup to induce vomiting or laxatives to empty the intestines. Intravenous fluids containing salts and dextrose may be given to correct dehydration and electrolyte imbalances. Pain medications are given for severe stomach pain. Atropine is given for muscarine-type mushroom poisoning. If illness comes on after eating unidentified mushrooms, vomiting should be induced immediately, and the vomitus saved for laboratory testing. Intravenous mannitol is sometimes used to treat severe ciguatera poisoning. Antihistamines may be effective in reducing the symptoms of histamine fish poisoning. In 2001, Japanese scientists made a synthetic version of ciguatoxin, an important step in developing an antibody to help diagnose ciguatera.

In mild cases of food poisoning, dietary modifications are often the only treatment necessary. During periods of active vomiting and diarrhea, people with food poisoning should avoid solid food for eight to 24 hours, and should increase fluids. Clear liquids should be consumed in small quantities. Once active symptoms stop, a diet of bland, easily digested foods such as broth, eggs, rice and other cooked grains, and toast is recommended

for two to three days. Milk products, spicy food, alcohol, sweets, raw vegetables, and fresh fruit should be avoided.

Expected results

Many cases of food poisoning clear up on their own within a week without medical assistance. There are usually few complications once possible dehydration has been addressed. Fatigue may continue for a few days after active symptoms stop, however. In the more severe types of poisoning, especially those involving neurotoxins, the respiratory muscles may become paralyzed. In such cases, death will result from asphyxiation unless there is medical intervention. Deaths due to food poisoning are rare and tend to occur in the very young, the very old, and in people whose immune systems are already weakened.

C. botulinum, is likely to cause serious illness or fatalities, even when ingested in very small quantities. Children affected by food poisoning from E. coli often need to be hospitalized. In some cases, E. coli toxins may be absorbed into the blood stream where they destroy red blood cells and platelets, which are important in blood clotting. About 5% of victims, regardless of age, develop hemolytic uremia syndrome, which results in kidney failure.

Prevention

Eighty-four percent of adults surveyed in 2001 were unaware that feces on beef and poultry was the main carrier of salmonella, campylobacter, and E. coli. Other than informing the public, food poisoning prevention efforts include:

• hot foods should be kept hot, and cold foods should be kept cold
• meat should be cooked to the recommended internal temperature; eggs should be cooked until no longer runny
• leftovers should be refrigerated promptly and food should never be left to stand at room temperature
• contact of utensils and surfaces with the juices of raw meats should be avoided
• fruits and vegetables should be washed before using
• unpasteurized dairy products and fruit juices should be avoided
• bulging or leaking canned foods or any food that smells spoiled should be discarded
• hands should be washed with soap before food preparation and after using the bathroom
• food preparation surfaces should be sanitized regularly
• infants under 12 months should not be fed honey, which may contain spores of C. botulinum
• proper canning and adequate heating of home-canned food before serving are essential (boiling for three minutes is recommended)

Taking Lactobacillus acidophilus or L. bulgaricus may help prevent food poisoning, especially when traveling. Populating the intestines with these bacteria will make it less likely that harmful bacteria are able to gain a foothold.

Resources

PERIODICALS

"Chicken and Beef are Often Contaminated with Feces." Health and Medicine Week (October 1, 2001).

Ramsay, Sarah. "Organic Chemistry Takes on Tropical Seafood Poisoning." The Lancet (December 1, 2001): 1878.

OTHER

FDA Center for Food Safety & Applied Nutrition. Foodborne Pathogenic Microorganisms and Natural Toxins Handbook. [cited October 2002]. <http://vm.cfsan.fda.gov/~mow/intro.html>.

Merck & Co., Inc. "E. coli O157:H7 Infection." The Merck Manual Online. [cited October 2002]. <http://www.merck.com/pubs/mmanual/section3/chapter28/28b.htm>.

Merck & Co., Inc. "Gastroenteritis." The Merck Manual Online. [cited October 2002]. <http://www.merck.com/pubs/mmanual_home/sec9/106.htm>.

Patience Paradox

Teresa G. Odle

food poisoning acute illness following the eating of foods contaminated by bacteria, bacterial toxins, natural poisons, or harmful chemical substances. It was once customary to classify all such illnesses as "ptomaine poisoning," but it was later discovered that ptomaines, the products of decayed protein, do not cause illness. The symptoms, in varying degree and combination, include abdominal pain, vomiting, diarrhea, headache, and prostration; more serious cases can result in permanent disability or death.

Bacterial Food Poisoning

In general, the bacteria that cause food poisoning do not affect the appearance, aroma, or flavor of food. The most common bacterial causes of food poisoning are Salmonella (see salmonellosis ), staphylococcus , Escherichia coli , Listeria monocytogenes,Shigella, and Campylobacter jejuni. The symptoms may be caused by toxins produced by the bacteria. The most serious type of food poisoning caused by bacterial toxins is botulism , which results from toxins made by the bacterium Clostridium botulinum.

Salmonella, most notoriously spread via raw eggs, develops from 6 to 72 hours after exposure. Symptoms include severe diarrhea, fever and chills, vomiting, and abdominal cramps and usually last from three to five days. Staphylococcal food poisoning is actually caused by the potent toxins that they produce. Typical sources are unrefrigerated ham, poultry, potato or egg salad, and custards. Carriers and food handlers with staphylococcal skin infections are mainly responsible for the spread of staphylococcus toxin poisoning. The onset of symptoms from such poisoning (similar to those of Salmonella infection) occurs abruptly one to six hours after ingestion of the polluted food. The illness lasts from 24 to 48 hours; fatalities are rare.

Outbreaks of food poisoning cases caused by infection with Shiga-toxin-producing strains of the usually harmless E. coli began to appear from the 1980s on, typically associated with consuming raw or undercooked ground meat or contaminated salad ingredients. Onset of symptoms comes one to eight days after eating the contaminated food. Symptoms include bloody diarrhea, nausea, and sporadic vomiting, with or without fever. It can progress to kidney failure and death, especially in children.

Listeriosis, caused by the bacterium Listeria monocytogenes, is spread in soft cheeses, undercooked meats, and prepared foods from delicatessen counters. Its onset is abrupt. Symptoms vary with the person's immune status and may include fever, muscle aches, fatigue, and nausea. The illness is especially serious for the very young or for pregnant women, who may miscarry or transmit blood infections or meningitis to the baby. In adults, the disease can progress to central nervous system complications, endocarditis, or pneumonia, and is an especially serious threat to the elderly.

Shigella is spread by contaminated food or from person to person (principally via a fecal-oral route). New strains of bacteria of the genus Shigella have been associated with food poisoning from ground meat. Symptoms include watery diarrhea, abdominal cramps, and bloody mucus in the stools.

Campylobacter enteritis is caused by either of two species of the Campylobacter bacterium. The bacterium is ubiquitous in uncooked poultry. Symptoms (diarrhea, fever, chills, headache) arise 2 to 11 days after exposure and last one to two weeks. Although usually mild, the infection can cause Guillain-Barré syndrome, a weakness of the peripheral nerves that can lead to paralysis and death.

Treatment for most bacterial food poisoning includes rest, sedation, and replacement of fluid loss if necessary. Antibiotics usually are used only in severe cases. Preventive measures in the home include thorough cooking and prompt refrigeration of meats and eggs, washing and peeling fruits and vegetables (and avoiding uncooked produce entirely if a person has a compromised immune system), washing of cooking surfaces and utensils that may have been contaminated by uncooked foods, and careful handwashing after use of the toilet.

Since the 1970s the number of food poisoning cases in the United States has gradually increased, and beginning in the 1980s more virulent organisms and more serious cases of food poisoning with complications leading to miscarriage, kidney failure, or death were observed. Some experts have attributed this to overprescription of antibiotics and the routine use of antibiotics as growth enhancers and to treat disease in livestock, practices that encourage the development of drug-resistant bacterial variants. An increase in the consumption of uncooked fresh produce has also contributed to the increase in food-borne illnesses. The increase in the number and severity of food poisoning cases have led to concern about food inspection and preparation methods, and to the Food and Drug Administration's approval of irradiating some high-risk foods to eliminate bacterial contamination. More stringent meat inspection procedures were put in place by the U.S. Dept. of Agriculture in 1996 in response to some of these concerns, and the FDA approved the irradiation of meat. The vast majority of food poisoning cases, however, involve fruits and vegetables, seafood, cheese, and products, such as juices or deli salads, made with them. In 2008 the FDA allowed spinach and iceberg lettuce to be irradiated to kill bacteria.

Food Poisoning by Natural Poisons and Metals

Nonbacterial food poisoning may occur after eating foods that contain a naturally occurring or acquired deleterious substance. Ingestion of poisonous mushrooms or toadstools (see mushroom poisoning ) may be followed in a matter of several minutes to two hours by severe thirst, abdominal cramps, diarrhea, vomiting, sweating, dizziness, confusion, collapse, coma, and, occasionally, convulsions. Poisoning may occur also after the ingestion of immature or sprouting potatoes because of the presence of solanine, an alkaloid. Mussels and clams that have fed on poisonous plankton also are a cause of food poisoning, since the poisonous substance is not destroyed by cooking. Ergot poisoning, caused by ingestion of rye grain infected with that fungus, causes damage to the blood vessels and gangrene, as well as gastrointestinal and neurologic symptoms.

It is also possible to take into the body poisons such as arsenic , lead , or mercury via foods that have been accidentally contaminated or sprayed with preservatives and not properly cleansed before ingestion. Food stored in containers lined with cadmium has been known to cause poisoning. Typical symptoms of this sort of food poisoning (diarrhea, vomiting) may occur right away; the nervous system and respiratory systems may be affected with continued exposure.

Bibliography

See J. P. Monahan, Food Poisoning (1984); J. N. Hathcock, ed., Nutritional Toxicology (1989); D. O. Cliver, ed., Foodborne Diseases (1990).

Food Poisoning

Forensic investigations can involve determining if an illness or death was related to the contamination of food, along with the origin of the contamination.

Food poisoning refers to an illness that is caused by the presence of bacteria, poisonous chemicals, or another kind of harmful compound in a food. Bacterial growth in the food is usually required. Food poisoning is different from food intoxication, which is the presence of pre-formed bacterial toxin in food.

There are over 250 different foodborne diseases. The majority of these are infections, and the majority of the infections are due to contaminating bacteria, viruses, and parasites. Bacteria cause the most food poisonings. The United States Centers for Disease Control and Prevention estimates that 76 million Americans become ill each year from food poisoning. The cost to the economy in medical expenses and lost productivity is estimated at $5–6 billion per year. Infections with the common foodborne bacteria called salmonella alone exact about a $1 billion economic toll per year.

Aside from the economic costs, food poisoning hospitalizes approximately 325,000 Americans each year, and kills more than 5,000 Americans.

Staphylococcus is the most common cause of food poisoning. The bacteria grow readily in foods such as custards, milk, cream-filled pastries, mayonnaise-laden salads, and prepared meat.

Two to eight hours after eating, the sudden appearance of nausea, stomach cramps, vomiting, sweating, and diarrhea signal the presence of food poisoning. Usually only minor efforts need be made to ease the symptoms, which will last only a short time even if untreated. Over-the-counter preparations to counter the nausea and diarrhea may help to cut short the course of the condition. Recovery is usually uneventful.

This syndrome is especially prevalent in summer months when families picnic out-of-doors and food can remain in the warmth for hours. Bacterial growth is rapid under these conditions in lunchmeat, milk, potato salad, and other picnic staples. The first course of eating may be without consequences, but after the food remains at ambient temperature for two hours or more, the probability of an infectious bacterial presence is increased dramatically. The second course or mid-afternoon snacks can lead to an uncomfortable sequel.

A far more serious form of illness is produced by a toxin secreted by the bacterium Clostridium botulinum. Botulism, which is frequently fatal, is a hazard of home canning of food and can develop from commercially canned products in which the can does not maintain the sterile environment within it. Affected food has no tainted taste. Normal heating of canned products in the course of food preparation will neutralize the toxin but will not kill the bacterial spores . These will open inside the body, the bacterium will multiply, and sufficient toxin can be produced to bring about illness.

Ingestion of botulism-contaminated food does not lead to the gastric symptoms usually associated with food poisoning. Botulism toxin affects the nervous system, so the symptoms of botulism may involve first the eyes, with difficulty in focusing, double vision, or other conditions, then subsequent difficulty in swallowing and weakness of the muscles in the extremities and trunk. Death may follow. Symptoms may develop in a matter of hours if the tainted food has been consumed without heating, or in four to eight days if the food is heated and the bacterium needs the time to grow.

The most common foodborne bacterial infections are caused by campylobacter, salmonella, and a type of Escherichia coli (E. coli) designated O157:H7. The latter is the cause of "hamburger disease." A virus known as calcivirus or Norwalk-like virus also is a common cause of food poisoning.

Escherichia coli O157:H7 lives in the intestines of cattle. When it contaminates food or water, it can cause an illness similar to that caused by salmonella. However, in a small number of cases, a much more devastating illness occurs. A condition called hemolytic uremic syndrome produces bleeding, can lead to kidney failure and, in the worst cases, can cause death.

Food poisoning often affects numbers of individuals who have dined on the same meal. This enables forensic scientists to trace the contaminated food and, if needed, determine the specific type of bacterium that caused the illness.

see also Poison and antidote actions.

food poisoning An acute illness caused by food that may be naturally poisonous or contaminated by certain types of pathogenic microorganisms. The most common type of food poisoning in the UK is that caused by the bacteria belonging to the genus Salmonella, which inhabit the alimentary canal of livestock. Other food poisoning bacteria include Staphylococcus aureus, Clostridium perfringens, Campylobacter jejuni, Listeria monocytogenes, and pathogenic Escherichia coli. Freezing and other types of food preservation can prevent the growth of the bacteria and thorough cooking will kill the microorganisms before the meat is eaten. However, food poisoning can result if frozen meat is not completely thawed at its centre before cooking, as it may not reach sufficiently high temperatures to kill the bacteria during cooking. Another type of food poisoning, known as botulism, is caused by toxins produced by the bacterium Clostridium botulinum, which can grow in badly preserved canned foods.

food poisoning May be due to (1)contamination with harmful bacteria or other micro‐organisms; (2)toxic chemicals; (3)adverse reactions to certain proteins or other natural constituents of foods;(4)chemical contamination. See also food‐borne disease.

The commonest bacterial contamination is due to species of Salmonella, Staphylococcus, Campylobacter, Listeria, Bacillus cereus, and Clostridium welchii. Very rarely, food poisoning is due to Clostridium botulinum, see botulism.

Staphylococcal poisoning causes rapid symptoms (within 2–4 hours): abdominal cramp, nausea, vomiting, and diarrhoea; recovery is normally rapid. Salmonellae produce an endotoxin which is not destroyed by cooking and causes acute gastro‐enteritis after 12–24 hours: nausea, vomiting, and diarrhoea may persist for several weeks.

food poisoning (food) n. an illness affecting the digestive system that results from eating food contaminated either by bacteria or bacterial toxins or, less commonly, by poisonous chemicals such as lead or mercury. It can also be caused by eating poisonous fungi, berries, etc. Symptoms include vomiting, diarrhoea, abdominal pain, and nausea. Food-borne infections are caused by bacteria of the genus Salmonella, Campylobacter, and Listeria in foods of animal origin. Toxin-producing bacteria causing food poisoning include those of the genus Staphylococcus, which rapidly multiply in warm foods; pathogenic Escherichia coli; and the species Clostridium perfringens, which multiplies in reheated cooked meals. See also botulism, gastroenteritis.

FOOD POISONING

DEFINITION

Food poisoning is a general term for health problems caused by eating contaminated food. Food may be contaminated by bacteria, viruses, toxins (poisons) from the environment, or toxins within the food itself. Symptoms of food poisoning usually include vomiting and diarrhea. Some toxins also affect the nervous system.

DESCRIPTION

Each year, millions of people suffer from bouts of vomiting and diarrhea that they blame on "something I ate." These people are usually correct. The U.S. Centers for Disease Control and Prevention (CDC) estimate that anywhere from six to thirty-three million cases of food poisoning occur in the United States each year. Many cases are mild. They pass so quickly that they are never diagnosed. On occasion, a severe outbreak affects a number of people. Newspapers, radio, and television may report on the outbreak.

Many kinds of food poisoning are caused by bacteria. The most common of these bacteria are Salmonella (pronounced SAL-mo-nel-uh), Staphylococcus aureus (pronounced STAFF-uh-lo-kock-us AW-ree-us), Escherichia coli O157:H7 (pronounced ESH-ur-ick-ee-uh KO-lie), Shigella (pronounced shih-GEL-uh), and Clostridium botulinum (pronounced klos-TRID-ee-um BOTCH-u-line-um). The pattern of disease caused by each type of bacterium is slightly different. Most of them cause inflammation of the intestines and diarrhea. Clostridium botulinum is an exception.

Food and water can also be contaminated by other agents, such as viruses, heavy metals (such as lead, cadmium, and mercury), and poisons produced within the food itself. Mushroom and shellfish poisoning, for example, are caused by poisons produced within the food itself.

Careless food handling creates conditions for the growth of bacteria that make people sick. Food can be contaminated at many different points during its trip from farm to table. Vegetables that are eaten raw, such as lettuce, may be contaminated by bacteria in the soil in which they were grown. They can also be contaminated during washing and packing. Home canning can also lead to food poisoning. Foods may be cooked at too low a temperature or for too short a time. Bacteria may not be killed.

Raw meats carry many bacteria that can cause food poisoning. The U.S. Food and Drug Administration (FDA) estimates that at least 60 percent of all raw poultry sold to consumers carries some disease-causing bacteria. Other raw meat products and eggs are also contaminated, but to a lesser degree. Thorough cooking kills these bacteria and makes the food harmless. However, properly cooked food can become recontaminated. It may come into contact with plates, cutting boards, counter tops, and utensils that have not been properly cleaned.

Food Poisoning: Words to Know

C. botulinum:

A very deadly bacteria that causes a disease known as botulism.

Campylobacter jejuni (C. jejuni ):

A bacteria that is the leading cause of bacterial diarrhea in the United States. It occurs in healthy cattle, chickens, birds, and flies.

Electrolytes:

Salts and minerals present in the body that produce electriallcy charged particles (ions) in body fluids. Electrolytes control the fluid balance in the body and are important in muscle contraction, energy generation, and almost all major biochemical reactions in the body.

Escherichia coli (E. coli ):

A bacteria that commonly causes food poisoning, most often from food products derived from cows, especially ground beef.

Platelets:

Blood cells needed to help blood clot.

Salmonella:

A bacteria that commonly causes food poisoning, most often from poultry, eggs, meat, and milk.

Shigella:

A bacterium that grows well in contaminated food and water, in crowded living conditions, and in areas with poor sanitation. It is transmitted by direct contact with an infected person or with food that has been contaminated by an infected person.

Staphylococcus aureus:

A bacteria that causes food poisoning, commonly found on foods that are kept at room temperature.

Cooked foods can also become contaminated in other ways. There are disease-causing bacteria everywhere in the environment. For example, experts estimate that half of all healthy people have the Staphylococcus aureus bacterium in their nasal (nose) passages and throat and on their skin and hair. These bacteria are easily transferred to food. A food handler may rub a runny nose and then touch freshly cooked food. Bacteria grow well at room temperature. They will rapidly reproduce to a level where they can make people sick. To prevent this growth, food must be kept hot or cold, but never just warm.

The food supply in the United States is probably the safest in the world. Still, anyone can get food poisoning. Serious outbreaks are rare. When they do occur, they strike some groups of people harder than others. The very young, the very old, and those with weakened immune systems are especially at risk. For example, people in these categories are twenty times more likely to become infected with the Salmonella bacterium than the general population.

People who travel outside the United States also have a greater chance of getting food poisoning. In many countries, less attention is paid to sanitation, water purification, and good food handling procedures. People living in institutions such as nursing homes are also more likely to get food poisoning.

CAUSES

Food poisoning is caused by toxins released by bacteria and other organisms. These toxins (except those from Clostridium botulinum ) cause inflammation

of the stomach and intestines. The result is abdominal (stomach) muscle cramping, vomiting, diarrhea, fever, and possibly dehydration. Dehydration is the process by which the body loses water faster than it should.

Salmonella

About fifty thousand cases of Salmonella poisoning were reported in the United States in 1995. The CDC estimates that between two and four million cases probably went unreported. Many people who have Salmonella poisoning are not aware that they have it. They do not see a doctor for treatment.

The main sources of Salmonella poisoning are egg yolks from infected chickens, raw and undercooked poultry and other meats, dairy products, fish, and shrimp. The bacterium is also found in many other foods. Egg yolks may be the most serious problem. The CDC estimates that 1 out of every 50 Americans consumes contaminated egg yolk in a year. Salmonella poisoning can be avoided by thoroughly cooking any of the foods in which it occurs. The bacteria are also found in the feces of pet reptiles, such as turtles, lizards, and snakes.

About 1 out of every 1,000 people get food poisoning from Salmonella. Of these people, two-thirds are under the age of twenty. The majority are under the age of nine. Most cases occur during the warm months between July and October.

FOOD IRRADIATION

Many methods for preserving food are available. These methods include freezing, drying, and canning. A method that may become more popular in the future is irradiation.

Irradiation is a process by which food is bombarded with high-energy radiation, such as X rays. This radiation kills bacteria in the food. Studies have shown that food irradiation is at least as effective as other methods of food preservation. For example, pork that is irradiated remains safe to eat for about ninety days. Pork kept under refrigeration is safe for no more than about forty days.

Today, the most common method for irradiating foods is with radioactive isotopes, such as cobalt 60 and cesium 137. Radioactive isotopes are materials that break apart and give off highenergy radiation.

Many people worry about the use of irradiation for preserving food. They fear that food may become radioactive and unsafe to eat. Or they worry that radiation may affect the taste, texture, or nutritional value of food.

Food irradiation is not a new technique. It has been used in other parts of the world for many years. The Food and Drug Administration (FDA) has given approval for the use of food irradiation in about a dozen kinds of foods. Whether that list becomes much longer remains to be seen.

Staphylococcus aureus

Staphylococcus aureus occurs everywhere in the environment. It is found in dust, air, and sewage. The usual method of transmission is by food handlers who use poor sanitary practices. For example, a cook may forget to wash his or her hands after using the bathroom. Bacteria can then be transferred from the cook's hands to food. Almost any kind of food can be contaminated in this way, but some foods are especially likely to be contaminated. These foods include salad dressings, milk products, cream pastries, and any food kept at room temperature.

It is difficult to estimate the number of Staphylococcus aureus poisoning cases that occur. Most cases are quite mild, and the patient never sees a doctor.

Escherichia coli (E. coli)

E. coli is a very common bacterium. It occurs in many different strains (forms). Some forms are beneficial. They may even be essential to the normal function of our digestive systems. The strain that causes most cases of food poisoning is E. coli O157:H7. Food poisoning caused by this bacterium occurs in about 3 out of every 10,000 people. The primary sources of E. coli are foods obtained from cows, such as dairy products and beef, especially ground beef.

Campylobacter jejuni (C. jejuni)

According to the FDA, Campylobacter jejuni (pronounced KAMP-puh-lo-BAK-tur jeh-JOO-ni) is the leading cause of bacterial diarrhea in the United States. Anyone can get food poisoning from C. jejuni. However, children under the age of five and young adults between the ages of fifteen and twenty-nine are most frequently affected.

C. jejuni occurs in healthy cattle, chickens, birds, and flies. It is also found in ponds and stream water. The bacterium is very potent (powerful). Consuming no more than a few hundred C. jejuni bacteria can cause a person to become ill.

Shigella

Shigella is a common cause of diarrhea in people who travel to developing countries. In these countries, sanitation practices may not be as well developed as they are in the United States. The Shigella bacterium grows well in contaminated food and water, in crowded living conditions, and in areas with poor sanitation. Shigella toxins infect the small intestine.

Clostridium botulinum (C. botulinum)

C. botulinum causes a disease known as botulism (pronounced BOTCH-u-liz-um). Two forms of botulism are known—adult and infant botulism. The C. botulinum bacterium is unlike any other bacterium in that it causes food poisoning in three ways.

First, C. botulinum is an anaerobic (pronounced AN-uh-RO-bik) bacterium. The term anaerobic means "able to live only in the absence of oxygen." That is, C. botulinum bacteria exposed to the air die quickly. Second, the toxins released by C. botulinum are neurotoxins. Neurotoxins are poisons that attack the nervous system, such as the brain and spinal cord. They may cause paralysis without producing any of the more traditional symptoms of food poisoning, such as vomiting and diarrhea. Third, botulism is a much more serious disease than other forms of food poisoning. People can die after consuming only very small amounts of the bacterium.

Adult botulism is usually caused by contaminated foods that are canned improperly at home. Less commonly, the C. botulinum bacterium is found in commercially canned foods. When foods are canned (at home or in a factory), they must first be heated to a high temperature. The temperature must be high enough to kill all C. botulinum bacteria that may be present. If the temperature is too low, some bacteria may survive. In such cases, conditions inside the can are an ideal setting for the bacteria to begin growing. No oxygen is present, and the canned food provides all the nourishment the bacteria need.

SYMPTOMS

How serious the symptoms of food poisoning are depends on many factors. These factors include the kind of bacteria, the amount consumed, and the individual's general health and sensitivity to the bacterial toxin.

Salmonella

Symptoms of Salmonella poisoning appear twelve to seventy-two hours after a person has eaten contaminated food. These symptoms are the traditional food poisoning symptoms, such as abdominal pain, diarrhea, vomiting, and fever. The symptoms usually last two to five days. In the most severe cases, dehydration can be a serious problem. People usually recover without being treated with antibiotics. However, they usually continue to feel tired for a week after the symptoms have passed.

Staphylococcus aureus

Symptoms of Staphylococcus aureus poisoning usually appear quickly, often within eight hours of eating the contaminated food. The most serious symptoms are vomiting, diarrhea, and severe abdominal cramps. These symptoms usually last three to six hours, and rarely more than twenty-four hours. Most people recover without medical assistance. Deaths are rare.

Escherichia coli (E. coli)

Symptoms of E. coli poisoning appear more slowly than symptoms of other kinds of food poisoning. These symptoms normally first arise one to three days after eating contaminated food. One symptom is severe abdominal cramps. Another symptom is diarrhea that is watery at first, but then becomes bloody. Both fever and vomiting are likely to be absent with E. coli poisoning. In most cases, the watery, bloody diarrhea disappears after one to eight days.

A possible complication of E. coli infection, especially in children under five and elderly people, is hemolytic uremic syndrome (HUS). This disease causes the kidneys to fail and red blood cells to be destroyed. Most people recover fully from HUS, but the disease can be fatal.

Campylobacter jejuni (C. jejuni)

The first symptoms of C. jejuni poisoning appear two to five days after eating contaminated food. These symptoms include fever, abdominal pain, nausea, headache, muscle pain, and diarrhea. The diarrhea can be watery or sticky. It may also contain blood. Symptoms of the infection last from seven to ten days. Relapses (reoccurrences of the infection) occur in about onequarter of all patients. Dehydration can be a serious complication.

Shigella

Symptoms of Shigella poisoning appear thirty-six to seventy-two hours after eating contaminated food. These symptoms are slightly different from other forms of food poisoning. The usual watery diarrhea, nausea, vomiting, abdominal cramps, and fever are present. But up to 40 percent of children infected with the bacterium show neurological (nervous system) problems. These symptoms include seizures, confusion, headache, lethargy (listlessness), and a stiff neck.

The disease usually lasts two to three days. Dehydration is a common complication. Most people recover on their own. But they may feel exhausted for days or weeks after symptoms have disappeared. Children who are malnourished (poorly fed) or who have weakened immune systems can die of the infection.

Clostridium botulinum (C. botulinum)

Symptoms of adult botulism usually appear eighteen to thirty-six hours after the contaminated food is eaten. The first signs of botulism are a feeling of weakness and dizziness, followed by double vision. As the bacteria spread through the nervous system, paralysis begins. The patient finds it difficult to speak and swallow. Eventually, the muscles of the respiratory (breathing) system are affected. The patient may die of asphyxiation (suffocation; pronounced as-FIK-see-A-shun). People who show the symptoms of botulism require immediate medical attention.

Infant botulism was first recognized in 1976. It differs from adult botulism in both causes and symptoms. Infant botulism occurs when a child under the age of one year inhales or swallows the spores of C. botulinum. Spores are reproductive cells from non-flowering plants, such as mosses and ferns. C. botulinum spores are found in the soil. A more common source in the case of food poisoning, however, is honey.

Once inside an infant's body, C. botulinum spores become stuck in the baby's intestines. They begin to grow and release their neurotoxin. Symptoms begin to appear very gradually. Initially, the baby is constipated. Eventually, it loses interest in eating, begins to drool, becomes weak and lethargic, and makes a very distinctive crying sound. Eventually the baby loses its ability to control its head muscles. Beyond that point, paralysis sets in throughout the baby's body.

DIAGNOSIS

An important step in diagnosing food poisoning is studying the behavior of groups of people. Doctors try to find out if a number of people have eaten the same food and have the same symptoms. If that is the case, the food may have been contaminated. Diagnosis of food poisoning can be confirmed with a stool culture. A sample of feces is taken from the patient. The sample can then be studied to see whether the bacteria that cause food poisoning are present. Laboratory tests can also be conducted on the contaminated food. The bacteria present can be detected.

The diagnosis of botulism presents different problems. First, the characteristics of botulism are very different from those of other forms of food poisoning. Second, a rapid diagnosis is essential. A person who has botulism can become ill and die very quickly.

Many cases of food poisoning are never diagnosed. People may not even realize that they are sick. In most cases, the symptoms of food poisoning disappear quickly.

TREATMENT

People with food poisoning should modify their diet during the period of illness. They should drink clear liquids frequently, but in small amounts. As their condition improves, soft, bland foods can be added to the diet. A commonly recommended diet is called the BRAT diet. The BRAT diet gets its name from the four foods it includes: banana, rice, applesauce, and toast. Milk products, spicy food, alcohol, and fresh fruit should be avoided until all symptoms disappear. These dietary changes are often the only treatment necessary for food poisoning.

In all cases of food poisoning except botulism, the major concern is dehydration. Diarrhea and vomiting both result in the loss of water and electrolytes from the body. Electrolytes are chemicals that control many important body functions. When they are lost, normal body functions may be disrupted. This problem can be especially serious in young children and elderly people.

Simple dehydration is easily treated. Over-the-counter (non-prescription) fluids that restore electrolytes can be purchased in any drug store. These fluids are usually pleasant tasting and restore lost water and electrolytes efficiently. If dehydration is serious, further treatment may be necessary. Fluids may have to be injected directly into a person's bloodstream.

In very serious cases of food poisoning, medications may be given to stop cramping and vomiting. Nothing should be done to stop diarrhea, however. Diarrhea helps remove toxins from the body.

In some cases, doctors may decide to use drugs to treat food poisoning. The most frequently prescribed antibiotics are a combination of trimethoprim and sulfamethoxazole (pronounced tri-METH-o-prim and SULL-fuhmeth-OCK-suh-zole, trade names Septra, Bactrim), ampicillin (pronounced AMP-ih-SIL-in, trade names Amcill, Polycill), or ciprofloxacin (pronounced SIP-ro-FLOK-suh-sin, trade names Ciloxan, Cipro).

The treatment of botulism is a much more difficult problem. A botulism antitoxin exists. The antitoxin counteracts the poison produced by C. botulinum. But it must be given within seventy-two hours after symptoms first appear. After that time, the antitoxin has no effect. The antitoxin also cannot be used on infants.

Both infants and adults who have botulism require hospital care. Patients may need to have a mechanical device to help them breathe until paralysis disappears.

Alternative Treatment

Alternative practitioners offer the same advice regarding diet modification as that described above. They also recommend taking charcoal tablets. Charcoal has the ability to attract and soak up toxins in the body. Other recommended treatments include two bacteria found in milk products, Lactobacillus acidophilus (pronounced LACK-toe-buh-sill-us a-suh-DAH-fuh-luss) and Lactobacillus bulgaricus (pronounced LACK-toe-buh-sill-us bul-GAR-ihkuss), and citrus seed extract.

A fluid to replace water and electrolytes can be made at home. It is made by adding one teaspoon of salt and four teaspoons of sugar to one quart of water. Two herbs that are recommended for treating forms of food poisoning other than botulism are Arsenicum album and Nux vomica.

PROGNOSIS

Except for botulism, most cases of food poisoning clear up on their own within a week without medical assistance. The patient may continue to feel tired for a few days after the symptoms disappear. As long as a person does not become dehydrated, there are usually no long-term symptoms. Deaths are rare. They tend to occur in the very young, the very old, and people with weakened immune systems.

Long-term effects are somewhat more common with Salmonella. Arthritis-like symptoms may occur three to four weeks after the original infection. Death from Salmonella is rare, but not unheard of. Most of these deaths have occurred among elderly people living in nursing homes.

Food poisoning caused by E. coli can also be serious, but usually in children rather than adults. The bacterium can attack platelets and red blood cells. Platelets are needed to make blood clot. In about 5 percent of the people infected with E. coli, this problem is so serious that their kidneys begin to fail. Kidney dialysis may be necessary. Kidney dialysis is a procedure in which a machine does the kidney's job of filtering out the body's waste products.

Botulism is the deadliest form of food poisoning. With prompt medical care, prognosis is good. Less than 10 percent of patients die. Without medical care, however, prognosis is very poor. The rate of death is very high.

PREVENTION

Food poisoning is almost entirely preventable. Good sanitation and food handling techniques are the key to avoiding the disease. The instructions to keep in mind are as follows:

• Keep hot foods hot and cold foods cold.
• Cook meat to the recommended internal temperature. Use a meat thermometer to be sure. Cook eggs until they are no longer runny.
• Refrigerate leftovers promptly. Do not let food stand at room temperature.
• Avoid contaminating surfaces and foods with the juices of uncooked meats.
• Wash fruits and vegetables before using.
• Purchase pasteurized dairy products and fruit juices. Pasteurized foods are heated to a temperature hot enough to kill the bacteria that cause food poisoning.
• Throw away bulging or leaking cans or any food that smells spoiled.
• Wash hands well before and during food preparation and after using the bathroom.
• Sanitize food preparation surfaces regularly.

FOR MORE INFORMATION

Books

Cody, Mildred McInnes. Safe Food for You and Your Family. Minneapolis: Chronimed Publishers, 1996.

Latta, Sara L. Food Poisoning and Foodborne Diseases. Hillside, NJ: Enslow Publishers, Inc., 1999.

Patten, Barbara J. Food Safety. Vero Beach, FL: The Rourke Book Company, Inc., 1997.

Scott, Elizabeth, and Paul Sockett. How to Prevent Food Poisoning : A Practical Guide to Safe Cooking, Eating, and Food Handling. New York: John Wiley & Sons, 1998.

Periodicals

U.S. Food and Drug Administration. "The Unwelcome Dinner Guest: Preventing Food-Borne Illness." FDA Consumer (December 1997).

Web sites

"Botulism (Clostridium botulinum )." [Online] http://www.cdc.gov/ncidod/diseases/foodborn/botu.htm (accessed on October 19, 1999).

Centers for Disease Control and Prevention. [Online] http://www.cdc.gov (accessed on October 19, 1999).

U.S. Food and Drug Administration. Center for Food Safety and Applied Nutrition. Bad Bug Book. [Online] http://www.cfsan.fda.gov (accessed on October 19, 1999).

Food Poisoning

Robin’s Story

What Is Food Poisoning?

How Does It Happen?

How Do People Know If They Have Food Poisoning?

Diagnosis

How Is Food Poisoning Treated?

Prevention

Resource

Food poisoning results from eating foods that contain bacteria or their toxic byproducts. This can happen when foods have not been properly stored or prepared. Food poisoning also can result from eating poisonous plants or animals.

KEYWORDS

for searching the Internet and other reference sources

Bacterial infections

Botulism

Digestion

E. coli

Gastroenteritis

Salmonella

Staphylococcus

Robin’s Story

Robin and her friends squeezed every pleasure they could into the early days of September, milking summer vacation for all it was worth. The make-your-own-sundae party at Robins was the best time they had all summer. But within a day or two of the party, Robin and her friends all were suffering from diarrhea, fever, stomach cramps, and had vomited more times than they had ever imagined possible. Why? Robin and her friends were among the nearly quarter million Americans who became ill after eating ice cream that fall. The culprit? Salmonella entérinais bacteria. Unseen, odorless, and tasteless, the microscopic creatures poisoned the ice cream ingredients on the truck ride to the ice cream factory. The reason? The truck had not been cleaned from its previous load: unpasteurized raw eggs, a prime breeding ground for Salmonella.

Avoiding Food Poisoning

• Bacteria need time to grow, so do not eat perishable foods that have been out of the refrigerator for more than 2 hours.
• Do not eat raw or undercooked eggs, poultry or meat.
• Meat and poultry should be well cooked, not pink in the middle.
• Do not eat raw or unpasteurized dairy products.
• Wash fruits and vegetables before eating.
• Wash all plates, cutting boards, counters, and utensils that have come into contact with raw meats or poultry thoroughly before using them for something else.
• Wash hands thoroughly between handling raw meat and other items.
• Wash hands thoroughly after using the bathroom.
• Wash hands thoroughly after having any contact with animals and reptiles (which sometimes carry bacteria on their skin).
• Make sure the refrigerator temperature is kept between 34 and 40 degrees Fahrenheit.

What Is Food Poisoning?

Food poisoning is caused by eating harmful bacteria or the poisons they produce. These bacteria live in soil, raw meat, raw milk products, pets, bugs, rodents, and on unwashed hands and food-related equipment. Food becomes contaminated when food handling, preparation, or equipment is unsanitary. The most common sources are unrefrigerated, perishable* food; raw or undercooked foods; or preserved foods that were not cooked at high enough temperatures.

* perishable

means able to spoil or decay, as in perishable foods.

Although the food in the United States is among the most clean and safe in the world, outbreaks of food poisoning kill about 9,000 people a year and cause between 6.5 and 33 million illnesses each year. Food poisoning is not contagious like chickenpox, but an infected person can pass along the infection by hand-to-hand contact (for example, serving food).

How Does It Happen?

Food poisoning occurs when bacteria or their toxic products are present in the foods we eat. They usually cause inflammation in the intestines, and the body does everything it can to get rid of them.

How Do People Know If They Have Food Poisoning?

People with mild cases of food poisoning may have diarrhea, fever, vomiting, and stomach pains. The first signs of food poisoning can appear as

80 Years Ago: A Kansas Cannery

poisoning that results from eating food contaminated by Clostridium botulinum bacteria is called “botulism.” The word “botulism” is derived from the Latin word “botulus,” which means sausage.

Originally, scientists believed that the botulinum toxin could only be produced in the presence of animal protein, as found in sausage. In 1919, however, a botulism outbreak was traced to canned vegetables from a commercial cannery in Kansas. That same year, another botulism scare involved canned olives. Both incidents prompted stricter regulatory control of food processing technology.

early as 1 hour after eating or up to 3 days later. These symptoms may occur in others who ate the same food.

Diagnosis

Doctors diagnose food poisoning by asking about symptoms; conducting laboratory “stool cultures,” which test for the presence of specific bacteria; and having food samples analyzed. Outbreaks may be investigated by the local or state department of health.

How Is Food Poisoning Treated?

Food poisoning lasts for 1 to 7 days and usually does not require hospitalization. Hospitalization is necessary for serious cases of certain types of food poisoning or when the diarrhea or vomiting has caused dehydration*. To treat dehydration, the doctor may give a person fluids intravenously, that is, directly into the veins. People also might be hospitalized if the infection spreads from the intestines to the rest of body. In some cases, doctors will give them antibiotics to fight the infection.

* dehydration

(dee-hy-DRAY-shun) Is loss of fluid from the body.

Prevention

Following three basic guidelines will help prevent food poisoning:

1. Do not eat perishable foods that have been at room temperature for more than 2 hours.
2. Wash hands and utensils before and after handling any food, after using the bathroom and after handling raw meat, poultry, or eggs.
3. Cook food thoroughly, and do not eat marinade from raw meat or poultry until it has been thoroughly boiled.

But even when individuals keep themselves and their food clean, contamination may have happened long before it comes into people’s kitchens, as with Robin’s ice cream. Food processors, growers, and distributors also need to take steps to keep food safe (for example, clean processing plants and safe and sanitary storage of food). The U.S. Department of Agriculture, the Food and Drug Administration, and local state and city Departments of Health have strict rules for these businesses that are carefully enforced.

See also

Bacterial Infections

Botulism

Resource

The U.S. Food and Drug Administration publishes a Bad Bug Book with fact sheets about many different foodborne toxins. http://vm.cfan.fda.gov/^mow/intro.html

food poisoning Acute illness caused by consumption of food that is itself poisonous or which has become poisoned or contaminated with bacteria. Frequently implicated are salmonella bacteria, found in cattle, pigs, poultry, and eggs, and listeria, sometimes found in certain types of cheese. Symptoms include abdominal pain, diarrhoea, nausea, and vomiting. Treatment includes rest, fluids to prevent dehydration and, possibly, medication. See also botulism; gastroenteritis

poisoning, food See food poisoning.