The incidence of foodborne disease caused by Salmonella enterica is increasing yearly, despite the growing body of information regarding these most common pathogens. We examined the growth of, and lipopolysaccharide (LPS) expression of three Salmonella species (S. typhimurium, S. enteritidis , and S. blockley) grown at different pH values and temperatures and to different stages of the growth cycle. Growth conditions were found to affect the compositions of the LPS molecules produced by the organisms. The Tricine-SDS-PAGE and immunoblot profiles of LPS from the three Salmonella species were in accordance with the chemical data. Altered LPS profiles at different growth conditions were noted. Such differences among the profiles include variations within core oligosaccharides and the presence of O-side chains. The results also show that S. enteritidis and S. blockley grown to their exponential and stationary phases of the growth cycle produced longer O antigens and greater amounts of O antigens than did S. typhimurium grown at different growth stages. Tricine-SDS-PAGE allowed excellent resolution of low molecular weight LPS and the core region of LPS.

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