2024 Salmonella Outbreaks: Food, Pets, and Public Health Risks

In 2024, the United States witnessed several significant salmonella outbreaks, raising major public health concerns. These outbreaks have been linked to various sources, including foods, pets, and even household environments. One of the most notable incidents involved contaminated eggs, which led to infections across multiple states. The Centers for Disease Control and Prevention (CDC) launched an extensive investigation, resulting in a recall to curb further spread. This outbreak brought renewed attention to the risks posed by contaminated food products and highlighted the importance of proper cooking techniques, such as fully cooking eggs and other animal products, to kill harmful bacteria.

Another major source of recent outbreaks has been backyard poultry, including chickens and ducks. Handling live birds without adequate hygiene practices can easily transmit salmonella from animals to humans. The CDC has warned the public about the dangers of close contact with these birds and their enclosures, as salmonella bacteria can live on feathers, droppings, and even in the environment. Recent public health messaging has reinforced the importance of handwashing and using proper protective gear when handling poultry to reduce the risk of infection.

Additionally, salmonella outbreaks have been traced to exotic pets, particularly pet reptiles like bearded dragons and small turtles. These animals are known carriers of salmonella and can shed the bacteria even if they appear healthy. Many people are unaware of this risk, which has led to new educational campaigns by the CDC emphasizing hygiene and safe handling for pet owners. Health experts recommend that people wash their hands thoroughly after handling reptiles and keep these pets away from areas where food is prepared.

Fresh produce has also emerged as a frequent carrier of salmonella. Recent outbreaks linked to contaminated cucumbers and fresh basil have prompted large-scale recalls and heightened public awareness about the risks associated with consuming raw fruits and vegetables. The Food and Drug Administration (FDA) continues to issue guidance on safely handling produce, advising consumers to wash fresh produce thoroughly and store it at safe temperatures.

The CDC and FDA play a critical role in investigating and controlling salmonella outbreaks, implementing recalls, and educating the public on preventive measures. These agencies stress the importance of proper food handling practices—such as cooking food to safe temperatures and avoiding cross-contamination in kitchens—to reduce the risk of infection.

These recent outbreaks underscore the ongoing need for public awareness and adherence to food and pet safety guidelines. Consistent vigilance in handling food and animals is essential for preventing future outbreaks and safeguarding public health.
2024 Salmonella Outbreaks: Food, Pets, and Public Health Risks

Genetic and Phenotypic Relationships of Salmonella within the Enterobacteriaceae Family

The genus Salmonella belongs to the family Enterobacteriaceae, which includes several important pathogenic bacteria. Members of this family are primarily Gram-negative, rod-shaped organisms that inhabit the intestinal tract of animals, including humans. Within the genus Salmonella, bacteria are related to one another both phenotypically—meaning they share observable characteristics such as shape, motility, and metabolic activity—and genotypically, as evidenced by their genetic makeup.

One notable feature of Salmonella is its DNA base composition, which consists of 50-52 mol% guanine (G) and cytosine (C). This range is closely aligned with the G+C content of other genera in the family Enterobacteriaceae, such as Escherichia, Shigella, and Citrobacter. These genera share a common evolutionary ancestry, which is reflected in their DNA sequences. The similarity in G+C content between these bacteria highlights a genetic closeness that is not only suggestive of their evolutionary relationships but also significant in their physiological traits, such as resistance to environmental stresses and antimicrobial agents.

Further supporting the genetic relationship among these organisms is the DNA sequence homology. The bacteria within the genus Salmonella share highly conserved DNA sequences with one another, reinforcing their close genetic ties. However, when we look beyond Salmonella, the genera most closely related in terms of DNA sequences are Escherichia, Shigella, and Citrobacter. This shared genetic material can result in overlapping pathogenic traits, such as the ability to cause gastrointestinal infections in humans, seen in both Salmonella and Shigella.

These relationships have been corroborated by techniques such as numerical taxonomy, which uses quantitative data to classify organisms based on phenotypic traits, and 16S ribosomal RNA (rRNA) analysis, a method widely employed in phylogenetics to determine evolutionary relationships. The latter has confirmed that Salmonella, Escherichia, Shigella, and Citrobacter cluster closely together, underscoring the significance of both phenotypic and genotypic data in understanding bacterial taxonomy and evolution.
Genetic and Phenotypic Relationships of Salmonella within the Enterobacteriaceae Family

Understanding Salmonellosis: Causes, Transmission, and Prevention

Salmonellosis is an illness caused by Salmonella bacteria. These bacteria, when ingested, can cause a range of gastrointestinal symptoms including cramps, nausea, vomiting, and diarrhea. There are multiple strains of Salmonella, all capable of causing illness.

Salmonella can be found in various environments such as soil, water, and raw foods. It is also present in the feces of some animals, particularly reptiles like turtles and snakes. Pets can be a common source of Salmonella infection in children. If an animal has fecal matter on its skin and a person touches it, they can transfer the bacteria to themselves and potentially develop salmonellosis.

Food is another major transmission route. Raw foods like eggs, milk, chicken, turkey, and other meats can harbor Salmonella if they come into contact with animal feces. If these foods are not processed or cooked thoroughly, the bacteria survive and can infect anyone who consumes them. Contaminated water or surfaces can also play a role in spreading the bacteria.

People infected with salmonellosis have the bacteria in their feces. If an infected person does not wash their hands properly after using the bathroom, they can contaminate food or surfaces they touch, thereby spreading the bacteria to others. This is particularly concerning with young children in diapers who may spread the bacteria to caregivers during diaper changes.

Preventing salmonellosis involves proper hygiene and food handling practices. Washing hands thoroughly with soap and water, especially after using the bathroom or handling animals, is crucial. Ensuring food is cooked to safe temperatures and avoiding cross-contamination in the kitchen can significantly reduce the risk of infection. Additionally, educating pet owners on the risks of Salmonella and how to handle their pets safely can help prevent transmission.

In recent years, awareness campaigns have increased, emphasizing the importance of food safety and proper hygiene. Public health organizations continue to monitor and manage outbreaks, providing guidelines to minimize the risk of salmonellosis and other foodborne illnesses.
Understanding Salmonellosis: Causes, Transmission, and Prevention

Salmonella Risks: Prevention and Protection for Vulnerable Population

Salmonella bacteria, commonly found in the feces of certain animals, particularly reptiles, pose a significant health risk to humans. Iguanas, for instance, are known carriers of Salmonella marina. This presents a unique challenge for pet owners, as the feces can easily contaminate a reptile's skin. When individuals handle these reptiles, they inadvertently transfer the bacteria to their hands. This highlights the crucial need for meticulous hand washing to reduce the risk of contracting salmonellosis.

Salmonella is not only limited to reptiles. Other strains of this bacteria can spread through foods contaminated with animal feces. This contamination often occurs when poultry, eggs, and beef are not processed according to stringent public health standards. Additionally, fruits and vegetables can become tainted by feces present in the soil where they are cultivated. The risk extends to prepared foods, particularly when infected food handlers neglect proper hand hygiene after using the bathroom.

Young children and infants are particularly vulnerable to Salmonella infections due to their developing immune systems, which are less equipped to combat the bacteria. Other at-risk groups include older adults, individuals with weakened immune systems, and those taking specific medications such as cancer drugs, antacids, or stomach acid suppression medications. In these higher-risk populations, Salmonella infections are more likely to result in severe complications.

One of the serious complications associated with Salmonella in these vulnerable groups is bacteremia, where bacteria enter the bloodstream. Once Salmonella spreads beyond the gastrointestinal tract, it can cause more severe symptoms and potentially life-threatening conditions.

Recent data from the Centers for Disease Control and Prevention (CDC) emphasize the importance of food safety and hygiene practices. Each year, Salmonella causes about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the United States alone. This underscores the necessity for ongoing public health education and stringent food processing regulations.

In conclusion, while Salmonella poses a significant health threat, especially to certain high-risk groups, diligent hygiene practices, particularly hand washing after handling reptiles or raw foods, can significantly reduce the risk of infection. Public awareness and adherence to food safety standards are critical in preventing the spread of this bacteria and safeguarding public health.
Salmonella Risks: Prevention and Protection for Vulnerable Population

Salmonellosis: Disease caused by Salmonella

Salmonellosis, an illness caused by the Salmonella bacteria, primarily affects the gastrointestinal system in humans. This infection typically leads to symptoms like diarrhea, abdominal cramps, fever, and vomiting, lasting for several days. In more severe cases, Salmonella can disseminate beyond the digestive tract, causing bloodstream infections (bacteremia) or localized infections in bones or cerebrospinal fluid, though these complications are relatively rare.

The discovery of Salmonella is credited to Daniel E. Salmon, an American scientist, in the late 1800s. However, it was actually Theobald Smith, one of his researchers, who deserves recognition for isolating and identifying these bacteria. Since then, scientists have categorized over 2,400 variations of Salmonella, which are broadly classified into two species: Salmonella enterica and Salmonella bongori.

These bacteria can be found in various environments, including the intestines of animals, particularly poultry, cattle, and reptiles. Contaminated food, especially raw meat, eggs, and unpasteurized dairy products, is a common source of human infection. Salmonella can also spread through contact with infected animals or their feces.

Efforts to control Salmonella infections involve strict food safety measures, such as proper cooking of food, pasteurization of dairy products, and thorough handwashing. Despite these efforts, approximately 40,000 cases of salmonellosis are reported annually in the United States alone, with many more cases likely going unreported due to mild symptoms or lack of medical attention.

In recent years, there have been notable developments in diagnosing Salmonella infections, including advanced molecular techniques for rapid identification and tracking of specific strains. This progress aids public health officials in responding swiftly to outbreaks and implementing targeted prevention strategies. Ongoing research continues to refine our understanding of Salmonella and enhance strategies to reduce its impact on public health.
Salmonellosis: Disease caused by Salmonella

Discovery of salmonella

Salmonella infections have been present in America since at least the early 1600s. Scholars studying the history of Jamestown in Virginia believe that typhoid fever was responsible for the deaths of over 6,000 settlers between 1607 and 1624.

Salmonella bacterium was first found by Soholerin in 1839, and it isolated by Eberth in 1880 from the mesenteric lymph nodes and spleen of a person died from typhoid fever.

Salmonella was first cultured from the intestines of pigs infected with classical swine fever, by Theobald Smith in 1855.

The bacterial strain was named after Dr Daniel Elmer Salmon, an American veterinary pathologist who ran the United States Department of Agriculture. Together with Theobald Smith, Salmon found Salmonella in hogs that succumbed to the disease known as hog cholera.

Salmonella bacteria as a causative agent for gastroenteritis was isolated by Gartner in 1888 from a fatal case of gastroenteritis in a young man who had eaten raw meat taken from a diseased cow.

In 1880, German pathologist Karl Eberth identified S. enterica. It was first cultured in 1884 by Georg Gaffky.

S. typhimurium was isolated by Loeffler in 1892 from an infected mouse. In 1896, Achard and Bensaud isolated an organism to which they gave the name Bacillus paratyphique and this organism according to Boycott (1911) was S. schottmuller.
Discovery of salmonella

Kauffmann-White scheme

Salmonella is named after an American bacteriologist, D. E. Salmon, who first isolated Salmonella choleraesuis from porcine intestine in 1884.

Prior to 1966, serovar “names” were assigned irrespective of subspecies, for example, Salmonella Marina, Salmonella Bongor, and Salmonella Daressalaam.

In 1966 it was proposed by Kauffmann that every Salmonella serovar is thought of as individual separate species. It is the most significant advance in the accurate definition of salmonellae of importance in human and veterinary medicine emerged from the pioneering serological studies of White, later amplified by Kauffmann.

There are currently 2,463 serotypes (serovars) of Salmonella. The antigenic formulae of Salmonella serotypes are defined and maintained by the World Health Organization (WHO) Collaborating Centre for Reference and Research on Salmonella at the Pasteur Institute, Paris, France (WHO Collaborating Centre), and new serotypes are listed in annual updates of the Kauffmann-White scheme.

The different species are serotyped according to three different antigens:
H (flagellar) antigen – may occur in either or both of two forms, phase 1 and phase 2
O (somatic) antigens
Vi (capsular) antigen

Once the O, H phase are identified, the antigenic formula can be used to identify the serotype by referring to a Kauffman-White reference catalog.

The first publication of the Kauffmann-White scheme listed 44 serovars. When F. Kauffmann retired in 1964, the scheme contained 958 serovars.
Kauffmann-White scheme

Salmonella Abortusovis

Salmonella Abortusovis is a bacterial pathogen that affects sheep, causing abortions and stillbirths in pregnant ewes and mortality in neonates. Abortion storms can occur when this organism is first introduced. The disease develops in the last weeks of pregnancy. Once it has become established in a flock, older ewes generally have good immunity, and abortions are typically limited to young or newly introduced animals.

Available epidemiological data indicated that Abortusovis serotype is rare in most countries and regions of the world except in Europe, where it is particularly common, with reported cases in France, Spain, Germany, Cyprus, Italy, Switzerland, Russia, and Bulgaria, southwest England and Wales and also in Western Asia.

Salmonella enterica subspecies enterica serovar (serotype) Abortusovis, which is usually shortened to S. enterica serovar Abortusovis or S. Abortusovis, is a member of the Enterobacteriaceae. It is an aerobic, Gram-negative rod.

Although Salmonella Abortusovis is the serotype most frequently associated with ovine salmonellosis, especially in Europe and Middle East, other Salmonella serovars including S. Typhimurium and S. Dublin have also been described as causative agents of abortion.

Sheep can be infected by ingestion, or via the conjunctiva, respiratory tract or genital tract. Most infections are thought to be acquired by ingestion. Salmonella Abortusovis mainly occurs in vaginal discharges, the placenta, aborted fetuses and infected newborns, although it has been documented in milk and colostrum, and rarely in the testes or preputial fluid of rams. Respiratory secretions might be infectious in sick young lambs.
Salmonella Abortusovis

Salmonella enterica serovar Enteritidis

In most of the salmonellosis outbreaks resulted from poultry products consumption, Enteritidis and Typhimurium serovars have been isolated.

In the late 1990s, Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) serogroup B and Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) serogroup D were the most frequently isolated serotypes, accounting for ∼50% of isolates from patients in the United States. Notable recent outbreaks of Salmonella infection have been linked to eggs, cheese, dry cereal, ice cream premix, a variety of fresh sprouts, juice, cantaloupes, and other fresh vegetables.

Salmonella Enteritidis has been the major cause of the food-borne salmonellosis pandemic in humans over the last 30 years, during which contaminated hen’s eggs were the most important vehicle of the infection. Eggs can be contaminated on the outer shell surface and internally. Internal contamination can be the result of penetration through the eggshell or by direct contamination of egg contents before oviposition, originating from infection of the reproductive organs.

Vertical transmission is very important especially in poultry related Salmonella infection caused by the serovar Enteritidis that has a special affinity for the reproductive system of chickens. In this case, transmission to progeny occurs by transovarian infection when the parent birds have systemic infection leading to infection of the ovary and developing eggs in the oviducts.

Human illness caused by Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) has drastically increased worldwide, and by the 1980’s Salmonella Enteritidis had replaced Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) as the primary cause of salmonellosis globally.
Salmonella enterica serovar Enteritidis

Salmonella contamination in raw foods

Sometimes Salmonella bacteria are found in raw foods. If these foods are not processed or cooked well, the bacteria stay alive in the food and can infect someone who eats it.

Factors which help an outbreak of food borne Salmonella gastro-intestinal infection are contamination of food with the Salmonella pathogen, the Salmonella pathogen should be in adequate numbers with highest viability.

Salmonellae is not known to release toxins into the contaminated food in which they are multiplying, but the ingested bacteria is responsible for the disease by multiplying in the intestine of the host and invading the gastro-intestinal tract.

Human carriers are generally less important than animals in transmission of Salmonella strains. Salmonella present on raw meat and poultry could survive if the product is not cooked to a safe minimum internal temperature, as measured with a food thermometer.

Meat, poultry, egg, dairy products, and fruits and vegetables are primary transmission vehicles; they may be undercooked, allowing the Salmonella strains to survive, or they may cross-contaminate other foods consumed without further cooking.

During the past few years, outbreaks of Salmonella illness have been linked to contaminated cucumbers, pre-cut melon, chicken, eggs, pistachios, raw tuna, sprouts, and many other foods.

The association between poultry and Salmonella genus has long since been recognized. During processing, certain stages including scalding, plucking (defeathering), evisceration, and chilling of carcasses have been recognized as likely cross-contamination pathways.

Salmonella spp. is able to survive for weeks in water and for years in soil if environmental conditions such as temperature, humidity, and pH are favorable. Low water activity (aw) represents a barrier to growth for many vegetative pathogens, including Salmonella spp. Processed foods such as powdered milk, chocolate, peanut butter, infant food, and bakery products are characteristically low-aw food products.
Salmonella contamination in raw foods

Salmonella pathogenesis

Salmonellae are ubiquitous human and animal pathogens, and salmonellosis, a disease that affects an estimated 2 million Americans each year, is common throughout the world.

Salmonella infections that involve invasive serotypes are often life threatening, necessitating appropriate and effective antibiotic therapy.

Salmonellosis includes several syndromes (gastroenteritis, enteric fevers, septicemia, focal infections, and an asymptomatic carrier state).

Gastroenteritis is the most common Salmonella infection worldwide, accounting for 93.8 million cases which result in 155,000 deaths per year

Most non-typhoidal salmonellae enter the body when contaminated food is ingested. Person-to-person spread of salmonellae also occurs. To be fully pathogenic, salmonellae must possess a variety of attributes called virulence factors. These include

(1) the ability to invade cells,
(2) a complete lipopolysaccharide coat,
(3) the ability to replicate intracellularly, and
(4) possibly the elaboration of toxin(s).

After ingestion, the organisms colonize the ileum and colon, invade the intestinal epithelium, and proliferate within the epithelium and lymphoid follicles.

Children below the age of 5 years, elderly people and patients with immunosuppression are more susceptible to Salmonella infection than healthy individuals. Almost all strains of Salmonella are pathogenic as they have the ability to invade, replicate and survive in human host cells, resulting in potentially fatal disease.
Salmonella pathogenesis

Salmonella Heidelberg

Salmonella is the most commonly diagnosed bacterial agent causing foodborne illness in the United States. Approximately 1.4 million illnesses and 600 deaths are estimated to be caused by Salmonella each year.

Typically, Salmonella Enteritidis, Salmonella Typhimurium and Salmonella Heidelberg are the three most frequent serotypes recovered from humans each year.

S. Heidelberg has increasingly been reported as cause of human salmonellosis worldwide.

S. Heidelberg is a bacterium that can cause severe illness in calves and humans. Calves infected with S. Heidelberg may develop diarrhea or die abruptly without any clinical signs. In Brazil, S. Heidelberg has been reported in poultry but it is infrequently isolated from pigs.

Salmonella Heidelberg was initially discovered in 1933 in Heidelberg, Germany. In 1954, it was isolated for the first time in the United States.

People infected with S. Heidelberg can develop diarrhea, fever, and abdominal cramps, which typically last from 4 to 7 days.

S. Heidelberg appears to be easily passed from sick or dead calves to people. The organism can be passed via direct contact with infected calves or via indirect contact, such as through cleaning the calf area.
Salmonella Heidelberg

Transmission of salmonella

Salmonella spp. are members of the family Enterobacteriaceae. They are gram negative, facultatively anaerobic rods. Salmonella spp. are classified into serovars (serotypes) based on the lipopolysaccharide (O), flagellar protein (H), and sometimes the capsular (Vi) antigens.

Salmonella are non-fastidious as they can multiply under various environmental conditions outside the living hosts. They do not require sodium chloride for growth, but can grow in the presence of 0.4 to 4%.

Salmonella is spread by the fecal-oral route and can be transmitted by
•food and water,
•by direct animal contact, and
•rarely from person-to-person.

They are carried asymptomatically in the intestines or gall bladder of many animals, and are continuously or intermittently shed in the feces. These bacteria are also shed in the feces of animals and humans that are ill. In addition, Salmonella spp. can be carried latently in the mesenteric lymph nodes or tonsils; these bacteria are not shed, but can become reactivated after stress or immunosuppression.

The main reservoirs for human infection are poultry, cattle, sheep and pigs. Infection in animals is maintained by recycling slaughterhouse waste as animal feed, fecal oral spread and fecal contamination of hatching eggs. Transmission occurs when organisms, introduced into the kitchen in poultry carcasses, meat or unpasteurized milk, multiply in food owing to inadequate cooking, cross-contamination of cooked foods and inadequate storage. Person-to-person spread is common in institutions such as hospitals.

When Salmonella bacteria are ingested, they pass through a person’s stomach and colonize the small and large intestine. There, the bacteria invade the intestinal mucosa and proliferate. The bacteria can invade the lymphoid tissues of the gastrointestinal tract and spread to the bloodstream.

Transmission of salmonella

Salmonella in macadamia nuts

Nuts have been identified as a vector for salmonellosis. At least 25 recalls were issued in 2015 in the United States due to Salmonella contamination of walnuts, pecans, macadamia nuts, pine nuts, almonds, and hazelnuts.

The U.S. Food and Drug Administration (FDA) posted at least a dozen recalls in 2015 involving macadamia nuts, and another three have been announced in 2016. All of this year’s recalls to date involved nuts from Mahina Mele Farm south of Captain Cook. The farm also had a recall in August 2015 of one lot of macadamia nuts and nut butters due to potential Salmonella contamination.

In February 2015, Whole Foods Market is recalling packaged raw macadamia nuts due to possible Salmonella contamination. In August 2016, Diamond brand macadamia nuts distributed to retail stores nationwide are under recall after an FDA-contracted lab confirmed Salmonella in a package of the nuts.

Because macadamia nuts are harvested from ground in orchards where organic fertilisers, eg. chicken manure may have been used, there are concerns for microbial quality of the finished product.

It may be possible for pathogens, eg. Salmonella and environmental spoilers, eg. coliforms and moulds to gain entry to macadamia kernels through occasional natural cracks in shells or by cross-contamination during factory cracking and processing.
Salmonella in macadamia nuts

Foods most likely to cause salmonellosis

Salmonellosis infection is caused by a Salmonella bacteria which was first found by Soholerin in 1839, and it isolated by Karl Eberth in 1880 from the mesenteric lymph nodes and spleen of a person died from typhoid fever.

Transmission is by the fecal–oral route whereby the intestinal contents of an infected animal are ingested with food or water.

Poultry and beef are considered to be important vectors of Salmonella infection. Ground turkey products have recently been implicated in outbreaks, raising concern that adherence to performance standards is insufficient to protect public health if some fraction of product, especially ground product that may not be adequately cooked, contains high levels of the pathogen.

Epidemiological studies indicated that in the USA 20,000 cases of Salmonellosis were reported during the period of (1970–1987), from which 26.3% were occurred due to consumption of poultry meat and its products.

Salmonella transmission to food processing plants and food production equipment is a serious public health issue. Salmonella can enter the food chain at any point: crop, farm, livestock feed, food manufacturing, processing and retailing.

A number of workers handle animals during slaughter and processing, and contamination is possible when Salmonella or any other pathogen is present on the equipment or the workers’ hands or clothing.

Eating contaminated foods, such as raw meat, poultry and eggs that have not been cooked properly, is the most common cause of the illness. As well, raw (unpasteurized) milk and raw milk products, and contaminated water, can also contain the bacteria.
Foods most likely to cause salmonellosis

Habitat of salmonella

Salmonella spp. are members of the family Enterobacteriaceae. They are gram negative, facultatively anaerobic rods. Salmonella spp. are classified into serovars (serotypes) based on the lipopolysaccharide (O), flagellar protein (H), and sometimes the capsular (Vi) antigens.

Salmonellae are widely distributed in nature. The main reservoir of these bacteria is the intestinal tract of men and warm-and cold-blooded animals, except for fish, mollusks and crustaceans, which may get contaminated after being fished.

Salmonella also can be found in soil, water, raw food, and the bowel movements (poop) of some animals, including reptiles like turtles and snakes. Zoonotic salmonellae are commonly described as foodborne pathogens, however, drinking water as well as natural waters are known to be an important source for the transmission of these enteric microorganisms.

Some kids get sick because of a pet or other animal. If poop gets on the animal's skin, the bacteria will get on the skin, too. Then if a person touches the animal, she can get the bacteria and might develop salmonellosis.

The natural habitat of Salmonella may be divided into three categories based on the specificity of the host and clinical pattern of the disease:
*highly adapted to men: Salmonella Typhi and Salmonella Paratyphi A, B and C, agents of typhoid fever;
*highly adapted to animals: Salmonella Dublin (bovines), Salmonella Choleraesuis and Salmonella Typhisuis (swine), Salmonella Pullorum and Salmonella Gallinarum (birds), responsible for animal paratyphoid.
*The third category includes most of the serovars that affect men and animals, called zoonotic Salmonella, responsible for worldwide-distributed foodborne diseases, and detected in most species of animals used for human consumption, wild and domestic animals.
Habitat of salmonella 

Eliminate salmonella by cooking method

Salmonellosis is a foodborne disease caused by the consumption of contaminated food by Salmonella species. Salmonella is a well-documented pathogen known to occur in a wide range of foods, especially poultry products.

The poultry and poultry products are often contaminated with potential pathogenic bacteria if proper hygienic practices are not followed at during processing, preparation and storage of chicken products, subsequently they become significant source of foodborne diseases.

Salmonella is often spread when we eat poorly cooked foods. Raw or undercooked eggs, meat and poultry are particularly high risk foods. Thoroughly cooking food will kill Salmonella.

Although the presence of Salmonella in poultry is relatively common, poultry can be safely consumed when it is cooked to a safe internal endpoint temperature.

Where possible, foods (poultry stuffing, etc.) should be cooked to temperatures (at least 65.6 ° C) at which it can be assumed that all Salmonella bacteria have been destroyed.
Eliminate salmonella by cooking method

Temperature 40°F and below inhibits the growth of Salmonella

Salmonella is the most common form of food poisoning, causing vomiting, fever, and stomach pain. There re actually three types of disease caused by Salmonella: Enteric fever caused by S. typhosa; septicemia caused by S. cholerasuis; and gastrointeritidis caused by S typhimurium and S. enteritidis.

Salmonellae in foods are destroyed by heating the food to at least 160° F for red meats and 185° F for poultry. In general, foods heated to an end-point temperature of 160°F or above will destroy Salmonella.

All foods should be held at temperatures of 4.4 °C or below when not being cooked, prepared for cooking or being served. This would not eliminate Salmonella organisms from foods, but it would prevent their growth in the foods so that their number would be too small to cause salmonellosis in healthy adults.
Temperature 40°F and below inhibits the growth of Salmonella

High risk group for salmonella infection

Salmonella are motile, Gram negative rods of the family Enterobacteriaceae. Humans typically acquire Salmonella, through the ingestion of contaminated food or water, although transmission by fomites or direct faecel-oral spread can occur. Children are at the highest risk for Salmonella infection.

Children under the age of 5 higher rates of Salmonella infection than any other aged group. In the United States, infants under the age of 1 year have the highest reported incidence rate of salmonellosis, with the highest rate in infants 2 months of age, and an abrupt decrease after infancy. Most cases are relatively mild.

Young children, older adults, those taking antibiotics, pregnant women, the elderly, and people with weakened immune systems are the most likely to have severe infections.
High risk group for salmonella infection

General characteristics of salmonella species

Salmonella grows in the temperature range of 2-47° C with rapid growth between 25 and 43° C. The minimum temperature for growth prevails at neutral pH and increases sharply with increasing acidity or alkalinity of the suspending medium.

The species are facultatively anaerobic, Gram-negative, straight, small (0.7-1.5 x 2. 0– 5. 0 μm) rods, which are usually motile with peritrichous flagella.

Salmonella species cause illness by means of infection, i.e. the organism grows and multiples in the host’s body and becomes established in or on the cells or tissue of the host.

Salmonella typhi

Salmonella multiply in the small intestine, colonizing and subsequently invading the intestinal tissues, producing an enterotoxin and causing an inflammatory reaction and diarrhea.

Cell envelope of Salmonella spp. consists of a complex lipopolysaccharide structure, which may function an an endotoxins. Once ingested, Salmonella viable cell are colonized in ileum and colon, by binding on the surface of epithelial cell an using type III secretion system to inject effector proteins directly into the host cell cytoplasm.
General characteristics of salmonella species