The Effects of Washing Treatments on the Composition of Salmonella Oranienburg

Abstract

Cells of Salmonella oranienburg grown in liquid media of water activity (awl O· 993 were washed in water and in solutions of sucrose, glycerol, N aCI, KCI, NH.Cl, and MgSO. at a range of aw? Retention of sodium and potassium by the cells and loss of compounds absorbing in the ultraviolet were measured. At pH 7· 5, cells retained most sodium after washing in water, while retention of potassium and ultraviolet-absorbing compounds was greatest after washing in isotonic sucrose and electrolyte solutions. Changes in the pH of washing solutions markedly affected retention of cell constituents. When washed in solutions of aw from 1·000 to 0'990, the contents of potassium and ultraviolet-absorbing compounds in the cells were a function of aw while the sodium content was largely dependent on the nature of the washing solute. These results are discussed and recommendations made concerning the choice of solutions for washing and suspending cells o£ this organism.