Salmonella is a genus of the family Enterobacteriaceae populated by a variety of Gram negative rod-shaped bacteria, many of which are pathogenic and cause a range of diseases in humans. Salmonellae possess 3 major surface antigens, the H or flagellar antigen (phase 1 and 2), the O or somatic antigen (part of the LPS moiety) and the Vi or capsular antigen (referred to as K in other Enterobacteriaceae). Salmonellae also possess the LPS endotoxin characteristic of Gram negative bacteria. This LPS is composed of an O polysaccharide (O antigen) an R core and the endotoxic inner Lipid A.