--- title: Redipor Growth Media Type - XLD Agar description: Xylose lysine deoxycholate agar (XLD agar) - a selective medium commonly used to isolate and differentiate enteric pathogens, especially Shigella species. image: https://www.cherwell-labs.co.uk/hubfs/XLD%20agar/xld-2.jpg --- [![analytichem_Logo+claim_RGB](https://www.cherwell-labs.co.uk/hs-fs/hubfs/analytichem_Logo+claim_RGB.png?width=7907&height=1706&name=analytichem_Logo+claim_RGB.png "analytichem_Logo+claim_RGB")](https://www.cherwell-labs.co.uk/) [![analytichem_Logo+claim_RGB](https://www.cherwell-labs.co.uk/hs-fs/hubfs/analytichem_Logo+claim_RGB.png?width=7907&height=1706&name=analytichem_Logo+claim_RGB.png "analytichem_Logo+claim_RGB")](https://www.cherwell-labs.co.uk/) ![50th Logo Cherwell logo final](https://www.cherwell-labs.co.uk/hubfs/50th%20Logo%20Cherwell%20logo%20final.svg) Search # Growth Media Type XLD Agar ### Xylose lysine deoxycholate (XLD) agar is a selective culture medium commonly used to isolate Salmonella and Shigella species.   [![REQUEST CERTIFICATE OF ANALYSIS](https://no-cache.hubspot.com/cta/default/2885977/0019290e-74e4-49b1-b332-58e602527c7e.png)](https://cta-redirect.hubspot.com/cta/redirect/2885977/0019290e-74e4-49b1-b332-58e602527c7e) ### Other common names This product is widely known under the XLD agar, although it can be referred to as xylose lysine deoxycholate agar.   ### Primary Use A moderately selective medium recommended for isolation and differentiation of enteric pathogens, especially Shigella species. ### **Technical characteristics** The typical medium composition: | **Typical formulation:** | **g/ltr** | | --- | --- | | Xylose | 3.5 | | L-Lysine | 5 | | Lactose | 7.5 | | Saccharose | 7.5 | | Sodium chloride | 5 | | Yeast extract | 3 | | Phenol red | 0.08 | | Sodium Desoxycholate | 2.5 | | Ferric ammonium citrate | 0.8 | | Sodium Thiosulfate | 6.8 | | Agar | 15 | Fresh pH 7.4 ±0.2 ### Applications XLD agar is a selective and differential medium for the isolation of enteric pathogens such as Shigella or Salmonella species from food, and environmental samples. It relies on xylose fermentation, lysine decarboxylation and production of hydrogen sulphide for the primary differentiation of shigellae and salmonellae from non-pathogenic bacteria. Desoxycholate is a selective agent which inhibits the growth of Gram-positive microorganisms. ### Appearance The prepared media should appear as clear with red or pinkish-red colouration. ### Organisms & morphology | **Microorganism** | **Observational appearance** | | --- | --- | | *Salmonella spp.* | Red with black center | | *Shigella* | Red colonies | | *Escherichia coli* | Yellow to yellow-red colonies | **[Download PDF version](https://www.cherwell-labs.co.uk/hubfs/Growth%20Media%20Types%20-%20XLD%20agar%202024%20-%20v2%201.pdf)** ### Typical incubation parameters XLD agar is incubated at 30 – 35 °C for 18 to 48 hours when culturing *Salmonella* as recommended in the Pharmacopoeia guidance for “Testing of products – Bile-Tolerant Gram Negative Bacteria – *Salmonella*”. ### Regulatory references USP<62> Microbiological Examination of Nonsterile Products: Test for Specified Microorganisms Table 1 | Test for Salmonella | | | | --- | --- | --- | | *Test/Medium* | *Property* | *Test Strains * | | Xylose Lysine Deoxycholate Agar | Growth promoting + indicative | *Salmonella* *enterica* subsp. *enterica* serovar Typhimurium or *Salmonella* *enterica* subsp. *enterica* serovar Abony | [Download PDF version](https://www.cherwell-labs.co.uk/hubfs/Growth%20Media%20Types%20-%20XLD%20agar%202024%20-%20v2%201.pdf) ### More information on our products   [ #### **Gamma Irradiated Prepared Media ** Gamma irradiated prepared media plates for environmental monitoring in pharmaceutical manufacture, cleanrooms and more ](https://www.cherwell-labs.co.uk/irradiated-media) [ #### **Poured Culture Media Plates ** Range of prepared culture media plates for environmental monitoring, non-critical hygiene, general purpose and selective laboratory media ](https://www.cherwell-labs.co.uk/poured-culture-media-plates) [ #### **Redipor® Barrier Pack ** Cherwell’s Redipor® Barrier pack prevents the penetration of Vaporised Hydrogen Peroxide gassing (VHP) to the plates. ](https://www.cherwell-labs.co.uk/hubfs/Redipor%20Barrier%20Pack%20VHP%20Resistant%20Packaging%20Illustration.pdf) ### Does Plate Choice Change Sampling Accuracy? 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