Chapter 13 Media for the isolation of Salmonella

Abstract

Conventional isolation of Salmonella, in food microbiology is accomplished by using cultural methods. Media for pre-enrichment, selective enrichment and isolation have been developed. Several official organisations for standardisation have developed reference methods for the isolation of Salmonella. In general these use one pre-enrichment medium, two different selective enrichment media and two or more isolation media. In this paper the main media used for conventional isolation of Salmonella are reviewed. Also some recent developments in culture media for Salmonella are described. Modified pre-enrichment media are sometimes required for specific cases, and can be accomplished by addition of supplements as ferrioxamine E or OxyraseTM to standard media or though the development of new media such as Universal Purpose Broth. For the selective enrichment procedure, motility enrichment in semi-solid media shows equal or better results than the use of the standard liquid selective media. Recently developed isolation media use different selective and diagnostic properties, such as glucuronate fermentation, acid formation from propylene glycol, fermentation of glycerol and addition of Tergitol 4 as selective agent. There seems to be a trend in the official Standards Organisations to follow the more recent developments but progress is slow.