Triple Sugar Iron Agar
Also known as：TSI · TSI Agar · T.S.I. Agar · Triple Sugar Iron Medium · TSI Medium
For the differentiation of Gram-negative enteric bacilli on the basis of carbohydrate fermentation and hydrogen sulphide production.
- Category
- Dehydrated Culture Media
- Dissolve per litre
- 64.62 g
- Pack sizes
- 500 g · 5 kg · 25 kg
- Certifications
- Halal
- Standard methods
- ISO 6579-1·FDA BAM
Data updated：2026-11-07
Brand cross-reference：BD Difco Triple Sugar Iron Agar · Oxoid Triple Sugar Iron Agar · Merck TSI Agar（ISO 6579-1、FDA BAM） Brand cross-reference
- Allergens
- Milk, Soy
Overview
Triple Sugar Iron Agar (TSI) is the slant medium for presumptive identification of enteric bacteria: glucose, lactose and sucrose with phenol red show the fermentation pattern in the colour of slant and butt, sodium thiosulfate and ferrous sulfate blacken hydrogen sulfide producers, and gas cracks or lifts the agar. Typical Salmonella give a red slant, yellow butt and black centre; E. coli turn the whole tube yellow with gas. The Taiwan FDA Salmonella and V. parahaemolyticus methods, the FDA BAM and ISO 6579-1 all specify it as the first confirmation step for suspect colonies. Food-grade raw materials, Halal certified.
Principle
Triple Sugar Iron Agar is a modification by Sulkin and Willett of the double-sugar iron medium, with sucrose added to the lactose and glucose of the original.¹ Peptone, meat extract, and yeast extract supply nitrogen, amino acids, vitamins, and growth factors. Lactose and sucrose are present at ten times the concentration of glucose, and phenol red serves as the pH indicator. Organisms that ferment only glucose produce a small amount of acid that turns the whole tube yellow initially; the slant reverts to red as the glucose is exhausted and amino acids are degraded aerobically, giving an alkaline slant over an acid butt. Organisms that ferment lactose or sucrose produce enough acid to keep both slant and butt yellow. Gas production is shown by bubbles or cracks in the agar. Sodium thiosulphate and ferric citrate detect hydrogen sulphide, which forms a black precipitate in the butt. The medium is used in the biochemical confirmation of Salmonella.²
What biochemical identification media are for
Biochemical identification media reveal whether a strain can use a particular substrate, read through colour change, gas production, or a zone of clearing. They remain the basis of conventional identification and confirmatory quality control. Each medium covers one characteristic, so several are normally read together alongside known positive and negative control strains.
Directions
Suspend 64.62 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Dispense into tubes. Sterilize by autoclaving at 121°C for 15 minutes. Allow to set in a slanted position to give a butt of approximately 2.5 cm and a long slant. Test the finished medium for performance using stable, standard control cultures.
Cultural response
| Test organism | ATCC | Growth |
|---|---|---|
| Salmonella enterica ser. Typhimurium | 14028 | Slant / Butt: alkaline / acid · Gas: + · H2S: + |
| Escherichia coli | 25922 | Slant / Butt: acid / acid · Gas: + · H2S: − |
| Shigella flexneri | 12022 | Slant / Butt: alkaline / acid · Gas: − · H2S: − |
| Pseudomonas aeruginosa | 27853 | Slant / Butt: alkaline / alkaline · Gas: − · H2S: − |
Product highlights
- Halal certified, suitable for the Malaysian, Indonesian, and Middle Eastern markets
- Manufactured to the standard formulation, 64.62 g per litre
- Performance verified against standard control strains before release (Salmonella enterica ser. Typhimurium, Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa)
- 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 5Confirmation / biochemicalNamed in the method as：Triple sugar iron (TSI) agar
- FDA BAM Chapter 6: ShigellaBAM Chapter 6Confirmation / biochemicalNamed in the method as：Triple sugar iron (TSI) agar
- FDA BAM Chapter 9: VibrioBAM Chapter 9Confirmation / biochemicalNamed in the method as：Triple sugar iron (TSI) 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）: Confirmation / biochemical; FDA BAM Chapter 6: Shigella（BAM Chapter 6）: Confirmation / biochemical; FDA BAM Chapter 9: Vibrio（BAM Chapter 9）: Confirmation / biochemical. 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 64.62 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, Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa. See the cultural response table and the specification sheet.
04What are the equivalent brand products and standard methods?
Cross-reference: BD Difco Triple Sugar Iron Agar, Oxoid Triple Sugar Iron Agar, Merck TSI Agar. Standard methods: ISO 6579-1, FDA BAM. Formulations may differ slightly between makers; refer to the specification sheet.
05How is this product prepared?
Suspend 64.62 g of powder in 1 L of purified water. Heat with continuous stirring and bring to the boil for 1 minute. Dispense into tubes. Sterilize by autoclaving at 121°C for 15 minutes. Allow to set in a slanted position to give a butt of approximately 2.5 cm and a long slant. Test the finished medium for performance using stable, standard control cultures.
06How 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. Sulkin S. E. and Willett J. C., 1940. A triple sugar-ferrous sulfate medium for use in identification of enteric organisms. J. Lab. Clin. Med., 25:649-653.
- 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.