Salmonellae are gram-negative, intracellular bacteria and belong to the Enterobacteriaceae family. There are more than 2,500 known serotypes distributed in animals and humans. In poultry, two highly specific serotypes, S. gallinarum and S.pullorum, produce the diseases known as fowl typhoid and pullorum. However, various serotypes of salmonellae known as paratyphi S. enteritidis, S. typhimurium and S. senftenberg can infect poultry and other species and settle in their internal organs without causing clinical signs or illnesses. This group of salmonellae is often linked to foodborne diseases in humans.