Salmonella food poisoning

Salmonella food poisoning
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Salmonella Food Poisoning

Salmonella Food Poisoning

Definition

Salmonella food poisoning is a bacterial food poisoning caused by the Salmonella bacterium. It results in the swelling of the lining of the stomach and intestines (gastroenteritis ). While domestic and wild animals, including poultry, pigs, cattle, and pets such as turtles, iguanas, chicks, dogs, and cats can transmit this illness, most people become infected by ingesting foods contaminated with significant amounts of Salmonella.

Description

Salmonella food poisoning occurs worldwide, however it is most frequently reported in North America and Europe. Only a small proportion of infected people are tested and diagnosed, and as few as 1% of cases are actually reported. While the infection rate may seem relatively low, even an attack rate of less than 0.5% in such a large number of exposures results in many infected individuals. The poisoning typically occurs in small, localized outbreaks in the general population or in large outbreaks in hospitals, restaurants, or institutions for children or the elderly. In the United States, Salmonella is responsible for about 15% of all cases of food poisoning.

Improperly handled or undercooked poultry and eggs are the foods which most frequently cause Salmonella food poisoning. Chickens are a major carrier of Salmonella bacteria, which accounts for its prominence in poultry products. However, identifying foods which may be contaminated with Salmonella is particularly difficult because infected chickens typically show no signs or symptoms. Since infected chickens have no identifying characteristics, these chickens go on to lay eggs or to be used as meat.

At one time, it was thought that Salmonella bacteria were only found in eggs which had cracked, thus allowing the bacteria to enter. Ultimately, it was learned that, because the egg shell has tiny pores, even uncracked eggs which sat for a time on a surface (nest) contaminated with Salmonella could themselves become contaminated. It is known also that the bacteria can be passed from the infected female chicken directly into the substance of the egg before the shell has formed around it.

Anyone may contract Salmonella food poisoning, but the disease is most serious in infants, the elderly, and individuals with weakened immune systems. In these individuals, the infection may spread from the intestines to the blood stream, and then to other body sites, causing death unless the person is treated promptly with antibiotics. In addition, people who have had part or all of their stomach or their spleens removed, or who have sickle cell anemia, cirrhosis of the liver, leukemia, lymphoma, malaria, louse-borne relapsing fever, or Acquired Immunodeficiency Syndrome (AIDS ) are particularly susceptible to Salmonella food poisoning.

Causes and symptoms

Salmonella food poisoning can occur when someone drinks unpasteurized milk or eats undercooked chicken or eggs, or salad dressings or desserts which contain raw eggs. Even if Salmonella -containing foods such as chicken are thoroughly cooked, any food can become contaminated during preparation if conditions and equipment for food preparation are unsanitary.

Other foods can then be accidentally contaminated if they come into contact with infected surfaces. In addition, children have become ill after playing with turtles or iguanas, and then eating without washing their hands. Because the bacteria are shed in the feces for weeks after infection with Salmonella, poor hygiene can allow such a carrier to spread the infection to others.

Symptoms appear about one-two days after infection, and include fever (in 50% of patients), nausea and vomiting, diarrhea, and abdominal cramps and pain. The diarrhea is usually very liquid, and rarely contains mucus or blood. Diarrhea usually lasts for about four days. The illness usually ends in about five-seven days.

Serious complications are rare, occurring most often in individuals with other medical illnesses. Complications occur when the Salmonella bacteria make their way into the bloodstream (bacteremia ). Once in the bloodstream, the bacteria can enter any organ system throughout the body, causing disease. Other infections which can be caused by Salmonella include:

  • bone infections (osteomyelitis )
  • joint infections (arthritis)
  • infection of the sac containing the heart (pericarditis)
  • infection of the tissues which cover the brain and spinal cord (meningitis )
  • infection of the liver (hepatitis)
  • lung infections (pneumonia )
  • infection of aneurysms (aneurysms are abnormal outpouchings which occur in weak areas of the walls of blood vessels)
  • infections in the center of already-existing tumors or cysts.

Diagnosis

Under appropriate laboratory conditions, Salmonella can be grown and then viewed under a microscope for identification. Early in the infection, the blood is far more likely to positively show a presence of the Salmonella bacterium when a sample is grown on a nutrient substance (culture) for identification purposes. Eventually, however, positive cultures can be obtained from the stool and in some cases from a urine culture.

Treatment

Even though Salmonella food poisoning is a bacterial infection, most practitioners do not treat simple cases with antibiotics. Studies have shown that using antibiotics does not usually reduce the length of time that the patient is ill. Paradoxically, it appears that antibiotics do, however, cause the patient to shed bacteria in their feces for a longer period of time. In order to decrease the length of time that a particular individual is a carrier who can spread the disease, antibiotics are generally not given.

In situations where an individual has a more severe type of infection with Salmonella bacteria, a number of antibiotics may be used. Chloramphenicol was the first antibiotic successfully used to treat Salmonella food poisoning. It is still a drug of choice in developing countries because it is so inexpensive, although some resistance has developed to it. Ampicillin and trimethoprim-sulfonamide have been used successfully in the treatment of infections caused by chloramphenicol-resistant strains. Newer types of anibiotics, such as cephalosporin or quinolone, are also effective. These drugs can be given by mouth or through a needle in the vein (intravenously) for very ill patients. With effective antibiotic therapy, patients feel better in 24-48 hours, the temperature returns to normal in three-five days, and the patient is generally recovered by 10-14 days.

Alternative treatment

A number of alternative treatments have been recommended for food poisoning. One very effective treatment that is stongly recommended is supplementation with Lactobacillus acidophilus, L. bulgaricus, and/or Bifidobacterium to restore essential bacteria in the digestive tract. These preparations are available as powders, tablets, or capsules from health food stores; yogurt with live L. acidophilus cultures can also be eaten. Fasting or a liquid-only diet is often used for food poisoning. Homeopathic treatment can work very effectively in the treatment of Salmonella food poisoning. The appropriate remedy for the individual and his/her symptoms must be used to get the desired results. Some examples of remedies commonly used are Chamomilla, Nux vomica, Ipecac, and Colchicum. Juice therapy, including carrot, beet, and garlic juices, is sometimes recommended, although it can cause discomfort for some people. Charcoal tablets can help absorb toxins and remove them from the digestive tract through bowel elimination. A variety of herbs with antibiotic action, including citrus seed extract, goldenseal (Hydrastis canadensis ), and Oregon grape (Mahonia aquifolium ), may also be effective in helping to resolve cases of food poisoning.

Prognosis

The prognosis for uncomplicated cases of Salmonella food poisoning is excellent. Most people recover completely within a week's time. In cases where other medical problems complicate the illness, prognosis depends on the severity of the other medical conditions, as well as the specific organ system infected with Salmonella.

Prevention

Prevention of Salmonella food poisoning involves the proper handling and cooking of foods likely to carry the bacteria. This means that recipes utilizing uncooked eggs (Caesar salad dressing, meringue toppings, mousses) need to be modified to eliminate the raw eggs. Not only should chicken be cooked thoroughly, until no pink juices flow, but all surfaces and utensils used on raw chicken must be carefully cleaned to prevent Salmonella from contaminating other foods. Careful handwashing is a must before, during, and after all food preparation involving eggs and poultry. Handwashing is also important after handling and playing with pets such as turtles, iguanas, chicks, dogs and cats.

Resources

ORGANIZATIONS

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. (800) 311-3435, (404) 639-3311. http://www.cdc.gov.

KEY TERMS

Carrier Someone who has an organism (bacteria, virus, fungi) in his or her body, without signs of illness. The individual may therefore pass the organism on to others.

Gastroenteritis Inflammation of the stomach and intestines. Usually causes nausea, vomiting, diarrhea, abdominal pain and cramps.

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Carson-DeWitt, Rosalyn. "Salmonella Food Poisoning." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. 31 Aug. 2016 <http://www.encyclopedia.com>.

Carson-DeWitt, Rosalyn. "Salmonella Food Poisoning." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Encyclopedia.com. (August 31, 2016). http://www.encyclopedia.com/doc/1G2-3451601437.html

Carson-DeWitt, Rosalyn. "Salmonella Food Poisoning." Gale Encyclopedia of Medicine, 3rd ed.. 2006. Retrieved August 31, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3451601437.html

Salmonella Food Poisoning

Salmonella food poisoning

Definition

Salmonella food poisoning is a bacterial infection that causes inflammation (swelling) of the lining of the stomach and intestines (gastroenteritis ). The causative bacteria is called Salmonella. While domestic and wild animals, including poultry, pigs, cattle, and pets such as turtles, iguanas, chicks, dogs, and cats can transmit this illness, most people become infected by ingesting foods contaminated with significant amounts of the causative bacteria.

Description

Improperly handled or undercooked poultry and eggs are the foods which most frequently cause salmonella food poisoning. Chickens are a major carrier of salmonella bacteria, which accounts for its prominence in poultry products. However, identifying foods which may be contaminated with salmonella is particularly difficult because infected chickens typically show no signs or symptoms. Since infected chickens have no identifying characteristics, these chickens go on to lay eggs or to be used as meat.

At one time, it was thought that salmonella bacteria were only found in eggs which had cracked, thus allowing the bacteria to enter. Ultimately, it was learned that, because the egg shell has tiny pores, even uncracked eggs which sat for a time on a surface (nest) contaminated with salmonella could themselves become contaminated. It is known also that the bacteria can be passed from the infected female chicken directly into the substance of the egg before the shell has formed around it.

Anyone may contract salmonella food poisoning, but the disease is most serious in infants, the elderly, and individuals with weakened immune systems. In these individuals, the infection may spread from the intestines to the blood stream and then to other body sites, causing death unless the person is treated promptly with antibiotics . In addition, people who have had part or all of their stomach or their spleen removed or who have sickle cell anemia , cirrhosis of the liver, leukemia, lymphoma, malaria, louse-borne relapsing fever, or acquired Immunodeficiency syndrome (AIDS ) are particularly susceptible to salmonella food poisoning.

Demographics

Although salmonella food poisoning occurs worldwide, it is most frequently reported in North America and Europe. Only a small proportion of infected people are tested and diagnosed, and as few as 1 percent of cases are actually reported. While the infection rate may seem relatively low, even an attack rate of less than 0.5 percent in such a large number of exposures results in many infected individuals. The poisoning typically occurs in small, localized outbreaks in the general population or in large outbreaks in hospitals, restaurants, or institutions for children or the elderly. In the United States, salmonella is responsible for about 15 percent of all cases of food poisoning.

Causes and symptoms

Salmonella food poisoning can occur when someone drinks unpasteurized milk or eats undercooked chicken or eggs, or salad dressings or desserts which contain raw eggs. Even if salmonella-containing foods such as chicken are thoroughly cooked, any food can become contaminated during preparation if conditions and equipment for food preparation are unsanitary.

Other foods can then be accidentally contaminated if they come into contact with infected surfaces. In addition, children have become ill after playing with turtles or iguanas and then eating without washing their hands. Because the bacteria are shed in the feces for weeks after infection with salmonella, poor hygiene can allow such a carrier to spread the infection to others.

Symptoms appear about one to two days after infection and include fever (in 50% of patients), nausea and vomiting , diarrhea , and abdominal cramps and pain . The diarrhea is usually very liquid and rarely contains mucus or blood. Diarrhea usually lasts for about four days. The illness usually ends in about five to seven days.

Serious complications are rare, occurring most often in individuals with other medical illnesses. Complications occur when the salmonella bacteria make their way into the bloodstream (bacteremia). Once in the bloodstream, the bacteria can enter any organ system throughout the body, causing disease. Other infections which can be caused by salmonella include:

  • bone infections (osteomyelitis)
  • joint infections (arthritis)
  • infection of the sac containing the heart (pericarditis)
  • infection of the tissues which cover the brain and spinal cord (meningitis)
  • infection of the liver (hepatitis)
  • lung infections (pneumonia)
  • infection of aneurysms (aneurysms are abnormal outpouchings which occur in weak areas of the walls of blood vessels)
  • infections in the center of already-existing tumors or cysts

Diagnosis

Under appropriate laboratory conditions, salmonella can be grown and then viewed under a microscope for identification. Early in the infection, the blood is far more likely to positively show a presence of the salmonella bacterium when a sample is grown on a nutrient substance (culture) for identification purposes. Eventually, however, positive cultures can be obtained from the stool and in some cases from a urine culture.

Treatment

Even though salmonella food poisoning is a bacterial infection, most practitioners do not treat simple cases with antibiotics. Studies have shown that using antibiotics does not usually reduce the length of time that the patient is ill. Paradoxically, it appears that antibiotics do, however, cause the patient to shed bacteria in their feces for a longer period of time. In order to decrease the length of time that a particular individual is a carrier who can spread the disease, antibiotics are generally not given.

In situations where an individual has a more severe type of infection with salmonella bacteria, a number of antibiotics may be used. Chloramphenicol was the first antibiotic successfully used to treat salmonella food poisoning. It is still a drug of choice in developing countries because it is so inexpensive, although some resistance has developed to it. Ampicillin and trimethoprim-sulfonamide have been used successfully in the treatment of infections caused by chloramphenicol-resistant strains. Newer types of antibiotics, such as cephalosporin or quinolone, are also effective. These drugs can be given by mouth or through a needle in the vein (intravenously) for very ill patients. With effective antibiotic therapy, patients feel better in 24 to 48 hours, the temperature returns to normal in three to five days, and the patient is generally recovered by ten to 14 days.

Prognosis

The prognosis for uncomplicated cases of salmonella food poisoning is excellent. Most people recover completely within a week's time. In cases in which other medical problems complicate the illness, prognosis depends on the severity of the other medical conditions, as well as the specific organ system infected with salmonella.

Prevention

Prevention of salmonella food poisoning involves the proper handling and cooking of foods likely to carry the bacteria. This means that recipes utilizing uncooked eggs (Caesar salad dressing, meringue toppings, mousses) need to be modified to eliminate the raw eggs. Not only should chicken be cooked thoroughly, until no pink juices flow, but all surfaces and utensils used on raw chicken must be carefully cleaned to prevent salmonella from contaminating other foods. Careful hand washing is a must before, during, and after all food preparation involving eggs and poultry. Hand washing is also important after handling and playing with pets such as turtles, iguanas, chicks, dogs and cats.

Parental concerns

Because children are notoriously bad at hand washing, parents want to be particularly vigilant to make sure that careful hand washing is followed, especially if someone in the home is actually ill with salmonella food poisoning. In this case, extra precautions should be taken. Children should not share foods, utensils, beverages, etc. Hand washing after toileting or diaper changes should be undertaken with extra care to avoid spreading the infection to others. The healthcare provider should give the family guidance regarding when a recovering child should return to school or daycare.

KEY TERMS

Carrier A person who possesses a gene for an abnormal trait without showing signs of the disorder. The person may pass the abnormal gene on to offspring. Also refers to a person who has a particular disease agent present within his/her body, and can pass this agent on to others, but who displays no symptoms of infection.

Gastroenteritis Inflammation of the stomach and intestines that usually causes nausea, vomiting, diarrhea, abdominal pain, and cramps.

Resources

BOOKS

Cleary, Thomas G. "Salmonella." In Nelson Textbook of Pediatrics. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2004.

Eisenstein, Barry I., and Dori F. Zaleznik. "Enterobacteriaceae." In Principles and Practice of Infectious Diseases. Edited by Gerald L. Mandell. London: Churchill Livingstone, Inc., 2000.

ORGANIZATIONS

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. Web site: <www.cdc.gov>.

Rosalyn Carson-DeWitt, MD

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Carson-DeWitt, Rosalyn. "Salmonella Food Poisoning." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. 31 Aug. 2016 <http://www.encyclopedia.com>.

Carson-DeWitt, Rosalyn. "Salmonella Food Poisoning." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Encyclopedia.com. (August 31, 2016). http://www.encyclopedia.com/doc/1G2-3447200497.html

Carson-DeWitt, Rosalyn. "Salmonella Food Poisoning." Gale Encyclopedia of Children's Health: Infancy through Adolescence. 2006. Retrieved August 31, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3447200497.html

Salmonella

Salmonella

Salmonella is the common name given to a type of food poisoning caused by the bacteria Salmonella enteritidis (other types of illnesses are caused by other species of Salmonella bacteria, including typhoid fever . When people eat food contaminated by S. enteritidis, they suffer gastroenteritis (inflammation of the stomach and intestines, with diarrhea and vomiting).

Salmonella food poisoning is most often caused by improperly handled or cooked poultry or eggs. Because chickens carrying the bacteria do not appear ill, infected chickens can lay eggs or be used as meat.

Early in the study of Salmonella food poisoning, it was thought that Salmonella bacteria were only found in eggs which had cracks in them, and that the infecting bacteria existed on the outside of the eggshell. Stringent guidelines were put into place to ensure that cracked eggs do not make it to the marketplace, and to make sure that the outside of eggshells were all carefully disinfected. However, outbreaks of Salmonella poisoning continued. Research then ultimately revealed that, because the egg shell has tiny pores, even uncracked eggs which have been left for a time on a surface (such as a chicken's roost) contaminated with Salmonella could become contaminated. Subsequently, further research has demonstrated that the bacteria can also be passed from the infected female chicken directly into the substance of the egg prior to the shell forming around it.

Currently, the majority of Salmonella food poisoning occurs due to unbroken, disinfected grade A eggs, which have become infected through bacteria which reside in the hen's ovaries. In the United States, he highest number of cases of Salmonella food poisoning occur in the Northeast, where it is believed that about one out of 10,000 eggs is infected with Salmonella.

The most effective way to avoid Salmonella poisoning is to properly cook all food which could potentially harbor the bacteria. Neither drying nor freezing are reliable ways to kill Salmonella. While the most common source for human infection with Salmonella bacteria is poultry products, other carriers include pets such as turtles, chicks, ducklings, and iguanas. Products containing animal tissues may also be contaminated with Salmonella.

While anyone may contract Salmonella food poisoning from contaminated foods, the disease proves most threatening in infants, the elderly, and individuals with weakened immune systems. People who have had part or all of their stomach or spleen removed, as well as individuals with sickle cell anemia, cirrhosis of the liver, leukemia, lymphoma, malaria , louse-borne relapsing fever, or acquired immunodeficiency syndrome (AIDS ) are particularly susceptible to Salmonella food poisoning. In the United States, about 15% of all cases of food poisoning are caused by Salmonella.

Salmonella food poisoning occurs most commonly when people eat undercooked chicken or eggs, sauces, salad dressings, or desserts containing raw eggs. The bacteria can also be spread if raw chicken, for example, contaminates a cutting board or a cook's hands, and is then spread to some other uncooked food. Cases of Salmonella infections in children have been traced to the children handling a pet (such as a turtle or an iguana) and then eating without first washing their hands. An individual who has had Salmonella food poisoning will continue to pass the bacteria into their feces for several weeks after the initial illness. Poor handwashing can allow others to become infected.

Symptoms of Salmonella food poisoning generally occur about 1272 hours after ingestion of the bacteria. Half of all patients experience fever; other symptoms include nausea, vomiting, diarrhea, and abdominal cramping and pain. The stools are usually liquid, but rarely contain mucus or blood. Diarrhea usually lasts about four days. The entire illness usually resolves itself within about a week.

While serious complications of Salmonella food poisoning are rare, individuals with other medical illnesses are at higher risk. Complications occur when the Salmonella bacteria make their way into the bloodstream. Once in the bloodstream, the bacteria can invade any organ system, causing disease. Infections which can be caused by Salmonella include: bone infections (osteomyelitis), infections of the sac containing the heart (pericarditis), infections of the tissues which cover the brain and spinal cord (meningitis ), and liver and lung infections.

Salmonella food poisoning is diagnosed by examining a stool sample. Under appropriate laboratory conditions, the bacteria in the stool can be encouraged to grow, and then processed and viewed under a microscope for identification.

Simple cases of Salmonella food poisoning are usually treated by encouraging good fluid intake, to avoid dehydration. Although the illness is caused by a bacteria, studies have shown that using antibiotics may not shorten the course of the illness. Instead, antibiotics may have the adverse effect of lengthening the amount of time the bacteria appear in the feces, thus potentially increasing others' risk of exposure to Salmonella. Additionally, some strains of Salmonella are developing resistance to several antibiotics.

Efforts to prevent Salmonella food poisoning have been greatly improved now that it is understood that eggs can be contaminated during their development inside the hen. Flocks are carefully tested, and eggs from infected chickens can be pasteurized to kill the bacteria. Efforts have been made to carefully educate the public about safe handling and cooking practices for both poultry and eggs. People who own pets that can carry Salmonella are also being more educated about more careful handwashing practices. It is unlikely that a human immunization will be developed, because there are so many different types of Salmonella enteritidis. However, researchers in 1997 produced an oral vaccine for poultry from genetically altered live Salmonella bacteria, currently undergoing testing, that may show the prevention of Salmonella bacteria from infecting meat or eggs. In 2001, two teams of researchers in England sequenced the genomes of both Salmonella Typhimurium (a common cause of food poisoning) and Salmonella Typhi the cause of typhoid fever). Data gathered from the project will improve diagnosis of Salmonella infections, and may eventually lead to a method of blocking its transmission in humans.

See also Antibiotic resistance, tests for; Bacteria and bacterial infection; Bacterial adaptation; Food safety

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Salmonella Food Poisoning

Salmonella food poisoning

Salmonella food poisoning, consistent with all food poisoning, results from the growth of the bacterium in food. This is in contrast to food intoxication, were illness results from the presence of toxin in the food. While food intoxication does not require the growth of the contaminating bacteria to reasonably high numbers, food poisoning does.

Salmonella is a Gram negative, rod-shaped bacterium. The gastrointestinal tracts of man and animals are common sources of the bacterium. Often the bacterium is spread to food by handling the food with improperly washed hands. Thus, proper hygiene is one of the keys to preventing Salmonella food poisoning.

The food poisoning caused by Salmonella is one of about ten bacterial causes of food poisoning. Other involved bacteria are Staphylococcus aureus, Clostridium perfringens, Vibrio parahaemolyticus, and certain types of Escherichia coli . Between 24 and 81 million cases of food borne diarrhea due to Salmonella and other bacteria occur in the United States each year. The economic cost of the illnesses is between 5 and 17 billion dollars.

Poultry, eggs, red meat, diary products, processed meats, cream-based desserts, and salad-type sandwich filling (such as tuna salad or chicken salad) are prime targets for colonization by species of Salmonella. The high protein content of the foodstuffs seems to be one of the reasons for their susceptibility. Contamination is especially facilitated if improperly cooked or raw food is held at an improper storage temperature, for example at room temperature. Proper cooking and storage temperatures will prevent contamination, as Salmonella is destroyed at cooking temperatures above 150° F (65.5 °C) and will not grow at refrigeration temperatures (less than 40°F, or 4.4°C). Also, contamination can result if the food is brought into contact with contaminated surfaces or utensils.

The vulnerable foods offer Salmonella a ready source of nutrients and moisture. If the temperature conditions are right for growth, the increase in numbers of Salmonella can be explosive. For example, from a starting population of a single live bacterium with a division time of 30 minutes, a population of over 500 million bacteria can be generated in just 15 hours.

The ingestion of contaminated foods leads, within hours, to the development of one or all of the following ailments: stomach cramps, vomiting, fever, headache, chills, sweating, fatigue, loss of appetite, and watery or bloody diarrhea. Prolonged diarrhea is dangerous, as the body can be depleted of fluids and salts that are vital for the proper functioning of organs and tissues. The resulting shock to the body can be intolerably lethal to infants and the elderly. As well, there is a possibility that the bacteria can spread from the intestinal tract to the bloodstream, leading to infections in other parts of the body.

There are hundreds are different forms, or strains, of Salmonella, varying in the antigenic composition of their outer surface and in the maladies caused. Concerning food poisoning, Salmonella enteriditis is of particular concern. This strain causes gastroenteritis and other maladies because of several so-called virulence factors the organism is armed with.

One virulence factor is called adhesin. An adhesin is a molecule that functions in the recognition and adhesion of the bacterium to a receptor on the surface of a host cell. In the case of Salmonella, the tube-like structures called fimbriae can perform this function. Other molecules on the surface of the bacterium can be involved also.

Another virulence factor is a compound called lipopolysaccharide (LPS for short). Depending on the structure, LPS can help shield the Salmonella surface from host antibacterial compounds. As well, part of the LPS, can lipid A, can be toxic to the host. The lipid A toxic component is also referred to as endotoxin. Salmonella also produces another toxin called enterotoxin . Other bacteria produce enterotoxin as well. The Salmonella enterotoxin is readily degraded by heat, so proper cooking of food will destroy the activity of the toxin. The enterotoxin remains inside the bacteria, so the toxin concentration increases with the increase in bacterial numbers.

Salmonella is not particularly difficult to identify, as it produces distinctive visual reactions on standard laboratory growth media. For example, on bismuth sulfide media the bacteria produce hydrogen sulfide, which produces jet-black colonies. Unfortunately for the individual who experiences a food poisoning event, the diagnosis is always "after the fact." Knowledge of the cause often comes after the miseries of the poisoning have come and gone. But, in those instances where the spread of the bacteria beyond the gastrointestinal tract has occurred, diagnosis is helpful to treat the infection.

The prospects of eliminating of Salmonella food poisoning using vaccination are being explored. The most promising route is to block the adhesion of the bacteria to host epithelial cells of the intestinal tract. Such a strategy would require the development of a vaccine with long lasting immunity . However, vaccine development efforts will likely be devoted to other illnesses. For the foreseeable future, the best strategy in preventing Salmonella food poisoning will remain the proper cooking of foods and the observance of good hygiene practices when handling food.

See also Food preservation

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Salmonella

Salmonella A genus of rod-shaped Gram-negative bacteria that inhabit the intestine and cause disease (salmonellosis) in humans and animals. They are aerobic or facultatively anaerobic, and most are motile. Salmonellae can exist for long periods outside their host, and may be found, for example, in sewage and surface water. Humans may become infected by consuming contaminated water or food, especially animal products, such as eggs, meat, and milk, or vegetables that have been fertilized with contaminated manure. The bacteria can also be transmitted from human or animal carriers by unhygienic food preparation. Various species of Salmonella cause gastroenteritis and septicaemia; typhoid fever and paratyphoid fever are caused by S. typhi and S. paratyphi, respectively.

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salmonella

sal·mo·nel·la / ˌsalməˈnelə/ • n. (pl. salmonellae / -ˈnelē/ ) a bacterium (genus Salmonella) that occurs mainly in the intestine, esp. a serotype causing food poisoning. ∎  food poisoning caused by infection with a such a bacterium: an outbreak of salmonella. DERIVATIVES: sal·mo·nel·lo·sis / -ˌneˈlōsis/ n.

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Salmonella

Salmonella (sal-mŏ-nel-ă) n. a genus of Gram-negative motile rodlike bacteria that inhabit the intestines of animals and humans. Certain species cause such diseases as food poisoning, gastroenteritis, and septicaemia. S. paratyphi a species that causes paratyphoid fever. S. typhi a species that causes typhoid fever.

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Salmonella

Salmonella (family Enterobacteriaceae) A genus of Gram-negative rod-shaped bacteria. Most species are motile with many flagella. The genus includes some important disease-causing bacteria, including the causal agents of typhoid fever, and some types of ‘food poisoning’.

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MICHAEL ALLABY. "Salmonella." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. 31 Aug. 2016 <http://www.encyclopedia.com>.

MICHAEL ALLABY. "Salmonella." A Dictionary of Plant Sciences. 1998. Encyclopedia.com. (August 31, 2016). http://www.encyclopedia.com/doc/1O7-Salmonella.html

MICHAEL ALLABY. "Salmonella." A Dictionary of Plant Sciences. 1998. Retrieved August 31, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O7-Salmonella.html

salmonella

salmonella Several species of rod-shaped bacteria that cause intestinal infections in human beings and animals. Salmonella typhi causes typhoid fever; other species cause gastroenteritis. The bacteria are transmitted by carriers, particularly flies, and in food and water.

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"salmonella." World Encyclopedia. 2005. Encyclopedia.com. 31 Aug. 2016 <http://www.encyclopedia.com>.

"salmonella." World Encyclopedia. 2005. Encyclopedia.com. (August 31, 2016). http://www.encyclopedia.com/doc/1O142-salmonella.html

"salmonella." World Encyclopedia. 2005. Retrieved August 31, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O142-salmonella.html

Salmonella

Salmonella Genus of bacteria of family Enterobacteriaceae. Common cause of food poisoning. Found in eggs from infected hens, sausages, etc.; can survive in brine and in the refrigerator; destroyed by adequate heating.

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DAVID A. BENDER. "Salmonella." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. 31 Aug. 2016 <http://www.encyclopedia.com>.

DAVID A. BENDER. "Salmonella." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (August 31, 2016). http://www.encyclopedia.com/doc/1O39-Salmonella.html

DAVID A. BENDER. "Salmonella." A Dictionary of Food and Nutrition. 2005. Retrieved August 31, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-Salmonella.html

salmonella

salmonellaAllah, calla, Caracalla, Haller, inshallah, pallor, Valhalla, valour (US valor), Whyalla •gabbler, tabla •ambler, gambler, rambler, scrambler •Adler, saddler •handler •angler, dangler, strangler, wrangler •tackler • trampler • antler • dazzler •Carla, challah, Douala, gala, Guatemala, Gujranwala, impala, kabbala, Kampala, koala, La Scala, Lingala, Mahler, Marsala, masala, nyala, parlour (US parlor), Sinhala, snarler, tala, tambala, Uppsala •garbler • chandler • sparkler •sampler •a cappella, Arabella, Bella, bestseller, Capella, cellar, Cinderella, citronella, Clarabella, corella, Daniela, Della, dispeller, dweller, Ella, expeller, favela, fella, fellah, feller, Fenella, Floella, foreteller, Heller, impeller, interstellar, Keller, Louella, Mandela, mortadella, mozzarella, Nigella, novella, paella, panatella, patella, predella, propeller, queller, quinella, repeller, rosella, rubella, salmonella, Santiago de Compostela, seller, smeller, speller, Stella, stellar, tarantella, teller, umbrella, Viyella •Puebla •assembler, dissembler, trembler •medlar, pedlar •ländler •fin de siècle, Hekla •Kepler •exempla, exemplar, Templar •tesla, wrestler •embezzler • Rockefeller •knee-trembler • saltcellar •bookseller • storyteller

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"salmonella." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 31 Aug. 2016 <http://www.encyclopedia.com>.

"salmonella." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (August 31, 2016). http://www.encyclopedia.com/doc/1O233-salmonella.html

"salmonella." Oxford Dictionary of Rhymes. 2007. Retrieved August 31, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-salmonella.html

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