For isolation and enumeration of Salmonella typhi and other Salmonella species. XLD AGAR, MODIFIEDis a differential media used for isolation and enumeration ofSalmonella typhiotherSalmonella species. Formulated as per ISO 6579 standard. Medium contains Yeast extracts as source ofvitamins and minerals. Sodium deoxycholate acts as a selective agent,which is inhibitory to Gram-positive bacteriaandsuppressesother enteric pathogens and enhances the growth of few enteric bacilli. Xylose as a fermentable carbohydrate,which is utilized by Salmonellaspecies. Fermentation of Xyloseleads to medium colour change to red indicated by Phenol redindicator. Medium also contains Lactose and Sucrose as the source of fermentable sugar. L-lysine is an essential amino acid source. Lysine is added to differentiate Salmonella species. Sodium chloride maintainsosmotic balance. Sodium thiosulphate and Ferric ammonium citrate helps in development of black centered colonies on production of hydrogen sulphide in the medium. Agar is added as a solidifying agent.