The literature on foodborne diseases has described in detail the global ubiquity of the genus Salmonella and the significance of members of this genus in the etiology, transmission, and pathogenesis of this group of bacteria in the context of food safety. As an infectious disease, salmonellosis continues to plague human populations throughout both the developing and the developed world. The organism’s relevance to foods of animal origin makes it the most widely investigated and studied of the foodborne zoonoses.

The rate of growth of Salmonella is dependent on temperature, pH, salinity, water activity, and nutrient level of the suspending medium, and is a reflection of the synergistic and antagonistic interactions between these environmental factors. The minimal temperature for growth of samonellae varies widely with the food type. The propensity of the organism to survive prolonged periods of time in frozen foods is well established, thus creating a challenge for one of the most accepted methods of traditional food safety practices.

The principal symptoms of salmonellosis (nontyphoidal) are nonbloody diarrhea, abdominal pain, fever, nausea, myalgia, vomiting, and prostration, generally appearing in 8-72 hours after an initial contact with the infectious agent. Nontyphoidal salmonellosis appears to predominate in children less than 5 years old and is a likely reflection of greater frequency of fecal - oral contamination in this age group, immaturity of the immune system, and reduced antibacterial activity of the microflora of the gut. The clinical course of nontyphoid infections is not limited to the acute and often self-limiting illness but may proceed to more serious complications, especially in the immune compromised.

Thyphoid (enteric) fever is a more serious form of salmonellosis. The onset of disease is characterized by malaise, lack of appetite, headache and a slight rise in temperature. Septicemia is usually evident 10 or more days after the onset of illness.

The infectious dose is influenced by several factors including strain virulence, age, and immune status of the patient. An important consideration in the pertinence of the infectious dose is the role of serotypes. Some foodborne disease reports have implicated some serotypes causing clinical symptoms after the consumption of less than 50 cells.

Host-adapted strains of the organism can adversely affect the productivity and viability of herds and flocks. The resulting pathologic effect of S. dublin in cattle, S. choleraesuis in swine, S. abortus-ovis in sheep, and the ubiquity of S. typhimurium and S. infantis in animal reservoirs heighten the entire importance of animal salmonellosis and the variables in ecology, transmission, pathogenesis, and public health relevance of the genus.

Salmonellae are a resourceful and defiant group of microorganisms that parasitize a broad range of hosts including insects, reptiles, amphibians, birds, and mammals. Salmonella serotypes possess distinctive host ranges, unique patterns of virulence and geographic distribution patterns that complicate the epidemiology and control. The problem of asymptomatic carriage by animals and birds, environmental contamination by rodents and other vectors magnifies the challenge. We have to combine resources to pursue a workable initiative to counter the different avenues of contamination.