Xylose Lysine Deoxycholate Agar
Also known as：XLD · XLD Agar · XLD Medium · Xylose Lysine Desoxycholate Agar
For the selective isolation and differentiation of enteric pathogens, particularly Salmonella and Shigella species, from food, water, and other materials.
- Category
- Dehydrated Culture Media
- Dissolve per litre
- 55.68 g
- Pack sizes
- 500 g · 5 kg · 25 kg
- Certifications
- Halal
Data updated：2026-11-06
Overview
Xylose Lysine Deoxycholate Agar (XLD) is the standard isolation plate for Salmonella: sodium deoxycholate suppresses Gram-positive bacteria, xylose, lactose and sucrose with phenol red, and the lysine decarboxylation reaction let Salmonella revert to alkaline red colonies after fermenting xylose, while sodium thiosulfate and ferric ammonium citrate give typical hydrogen sulfide producers a black centre; Shigella are red without a black centre and coliforms are yellow. Specified by ISO 6579-1, the FDA BAM and the Taiwan FDA Salmonella method. Contains dye and deoxycholate, so heat to dissolve without autoclaving, as the directions describe. Food-grade raw materials, Halal certified.
Principle
Xylose Lysine Deoxycholate Agar was developed by Taylor for the isolation and differentiation of enteric pathogens.¹ Yeast extract supplies nitrogen, vitamins, and growth factors, and sodium chloride maintains the osmotic equilibrium. Sodium deoxycholate inhibits Gram-positive bacteria. Xylose is fermented by most enteric bacteria except Shigella. Salmonella ferments xylose but, once it is exhausted, decarboxylates lysine, producing alkaline conditions that return the phenol red indicator to red. Lactose and sucrose, present in excess, are fermented by coliforms, maintaining acid conditions and yellow colonies. Sodium thiosulphate and ferric ammonium citrate detect hydrogen sulphide, so that H2S-producing organisms form colonies with black centres. Typical Salmonella colonies are red with black centres, and Shigella colonies are red without black centres. The medium is specified as the first plating medium for the detection of Salmonella in food and animal feed.²
Directions
Suspend 55.18 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. DO NOT AUTOCLAVE. Cool to 45-50°C in a water bath, avoiding prolonged heating. Mix well and pour into sterile Petri plates. Test the finished medium for performance using stable, standard control cultures.
Cultural response
| Test organism | ATCC | Growth |
|---|---|---|
| Salmonella enterica ser. Typhimurium | 14028 | good-luxuriant |
| Salmonella enterica ser. Enteritidis | 13076 | good-luxuriant |
| Shigella flexneri | 12022 | good |
| Escherichia coli | 25922 | inhibited-partial |
| Enterococcus faecalis | 29212 | inhibited |
Product highlights
- Halal certified, suitable for the Malaysian, Indonesian, and Middle Eastern markets
- Manufactured to the standard formulation, 55.68 g per litre
- Performance verified against standard control strains before release (Salmonella enterica ser. Typhimurium, Salmonella enterica ser. Enteritidis, Shigella flexneri, Escherichia coli, Enterococcus faecalis)
- Available in 500 g / 5 kg / 25 kg, from laboratory to industrial scale
- COA, specification sheet, and technical data sheet available; samples on request
- Manufactured in Taiwan with reliable supply
FDA BAM methods
This product corresponds to a medium used in the chapters of the US FDA Bacteriological Analytical Manual (BAM), the reference methods for FDA regulatory testing. Follow the current online edition of each chapter.
- FDA BAM Chapter 5: SalmonellaBAM Chapter 5Isolation plateNamed in the method as：Xylose lysine desoxycholate (XLD) agar
BAM specifies methods and media formulations; it does not certify brands. Add supplements as the chapter requires, and verify media against reference strains under your quality system.
Frequently asked questions
01Does this medium meet FDA BAM methods?
BAM specifies methods and formulations, not brands. This product corresponds to a medium used in: FDA BAM Chapter 5: Salmonella（BAM Chapter 5）: Isolation plate. It is manufactured to the standard formulation and ships with a COA per batch; add supplements as the chapter requires and follow the current online edition.
02How much powder per litre?
Use 55.68 g per litre of deionised water; preparation and sterilisation conditions are given on the specification sheet.
03Which organisms is it suitable for?
Enterobacteriaceae, Gram-negative, Pathogens, Salmonella, Shigella, Salmonella enterica ser. Typhimurium, Salmonella enterica ser. Enteritidis, Shigella flexneri, Escherichia coli, Enterococcus faecalis. See the cultural response table and the specification sheet.
04How is this product prepared?
Suspend 55.18 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. DO NOT AUTOCLAVE. Cool to 45-50°C in a water bath, avoiding prolonged heating. Mix well and pour into sterile Petri plates. Test the finished medium for performance using stable, standard control cultures.
05How do I request a bulk quotation, and can you provide a COA?
Yes. This product is available in 500 g, 5 kg, 25 kg. Tell us your application and volume when requesting a quotation; we reply within one working day and can supply the COA, specification sheet, and technical data sheet.
Further reading
- FDA BAM Culture Media Cross-Reference: Which Media Each BAM Chapter Uses and the STBIO EquivalentAerobic plate count, coliforms and E. coli, Salmonella, Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, Vibrio, Clostridium perfringens, yeasts and moulds and Cronobacter: the media named in each FDA Bacteriological Analytical Manual chapter, matched to Taiwan-made dehydrated media for US laboratories qualifying a second source.
- Which Culture Media Do Taiwan FDA Food Microbiology Methods Specify? Cross-Reference for 21 Announced MethodsAerobic plate count, coliforms, E. coli, Enterobacteriaceae, Salmonella, Staphylococcus aureus, Listeria monocytogenes, lactic acid bacteria, yeasts and moulds, Bacillus cereus, Vibrio parahaemolyticus, Clostridium perfringens and Cronobacter: the media named in each Taiwan FDA (TFDA) announced method, matched to Taiwan-made products.
References
- 1. Taylor W. I., 1965. Isolation of shigellae. I. Xylose lysine agars; new media for isolation of enteric pathogens. Am. J. Clin. Pathol., 44:471-475.
- 2. ISO 6579-1, Microbiology of the food chain — Horizontal method for the detection, enumeration and serotyping of Salmonella — Part 1: Detection of Salmonella spp., International Organization for Standardization, Geneva.