| The diagnosis of salmonellosis is often complicated by the presence of background flora and other Enterobacteriaceae on an agar plate. The presence of the selective agent, Tergitol-4, in XLT-4 Agar inhibits many of the background flora that can be problematic on other plating media. In addition, chemical and pH changes within the medium allow Salmonella spp. (black colonies) to be differentiated from organisms, such as E. coli (yellow colonies) and Shigella spp. (red colonies). The enhanced selectivity of XLT-4 Agar saves time, by reducing the need for further identification procedures, and results in fewer false presumptive positive colonies when compared to other Salmonella plating media. For further information about Oxoid XLT-4 Agar and other products for the growth and identification of Salmonella species available from Oxoid, contact Val Kane using the contact details at the top of this page. Reference: 1. WHO Fact Sheet No 124, January 2002, Foodborne diseases, emerging. |