Thermo Scientific™ Oxoid™ Muller-Kauffmann Tetrathionate-Novobiocin Broth (MkTTn)

Thermo Scientific™ Oxoid™ Muller-Kauffmann Tetrathionate-Novobiocin Broth (MKTTn) is a highly selective enrichment medium for the isolation of Salmonella species from food, clinical, and environmental samples. It is designed for use in tandem with Oxoid Novobiocin Selective Supplement (SR0181) to inhibit competing flora such as Proteus species, ensuring accurate detection of Salmonella. The medium conforms to ISO 6579:2002 standards, making it ideal for global applications in food safety, clinical diagnostics, and research laboratories.

Composition (Typical Formula)

† Equivalent to 47.8g of sodium thiosulfate pentahydrate.

Preparation Instructions

1. Suspend 89.5g of MKTTn powder in 1 litre of distilled water. Mix thoroughly and bring to a boil.
2. Cool the solution to below 45°C.
3. Before use:
   • Add 20ml of iodine-iodide solution (prepared separately).
   • Add the contents of 4 vials of Oxoid Novobiocin Selective Supplement (SR0181) reconstituted as directed.
4. Mix well and aseptically dispense into sterile containers.
5. Use the medium immediately after preparation.

Applications

• Food Safety:
  • Isolation of Salmonella species from contaminated food products.
• Clinical Diagnostics:
  • Detection of Salmonella in stool and other clinical samples.
• Environmental Testing:
  • Monitoring water and sewage for Salmonella contamination.

Technique

1. Pre-enrich the sample in Buffered Peptone Water (BPW) (ISO) CM1049 at 37°C ± 1°C for 16-20 hours.
2. Transfer:
   • 1ml of BPW culture to 10ml MKTTn Broth.
   • 0.1ml of BPW culture to 10ml RVS Broth (CM0866).
3. Incubate:
   • MKTTn at 37°C ± 1°C for 24 ± 3 hours.
   • RVS at 41.5°C ± 1°C for 24 ± 3 hours.
4. Subculture both broths onto XLD Agar (CM0469) and another agar of choice. Incubate at 37°C ± 1°C for 24 ± 3 hours.
5. Confirm presumptive Salmonella colonies with biochemical and serological techniques.

Quality Control

† Indicates selective growth of Salmonella species.

Storage and Shelf Life

1. Dehydrated Medium:
   • Store at 10–30°C.
   • Use before the expiration date printed on the label.
2. Prepared Medium:
   • Store at room temperature.
   • Prepared medium containing iodine/iodide solution and Novobiocin Selective Supplement (SR0181) must be used immediately.

Physical Properties

• Dehydrated Medium:
  • Pale green, free-flowing powder.
• Prepared Medium:
  • Pale green, opaque suspension with a heavy deposit upon standing.

Advantages

1. Enhanced Selectivity:
   • The inclusion of brilliant green, ox bile, and novobiocin inhibits competing organisms, ensuring reliable Salmonella isolation.
2. ISO Compliance:
   • Conforms to ISO 6579:2002 standards, ensuring global applicability in microbiological testing.
3. Proven Performance:
   • Developed through extensive validation, including large-scale international studies.
4. Ease of Use:
   • Simple preparation with freeze-dried supplements for convenience.

Why Choose Thermo Scientific™ Oxoid™ MKTTn?

The Muller-Kauffmann Tetrathionate-Novobiocin Broth is an indispensable medium for laboratories engaged in the detection and isolation of Salmonella species. Its optimized formulation, ISO compliance, and compatibility with complementary media like RVS Broth and XLD Agar ensure reliable results across food safety, clinical diagnostics, and research applications.