MKTTn Broth Base (AS-1301) | ISO 6579 Salmonella Enrichment
Mueller Kauffmann Tetrathionate Novobiocin Broth Base
MKTTn Broth Base • Selective enrichment medium for Salmonella spp.
Mueller Kauffmann Tetrathionate Novobiocin Broth Base (MKTTn) is a selective enrichment medium used for the recovery of Salmonella spp. from foods, animal feeds, and environmental samples. When completed with iodine-iodide solution and novobiocin supplement, the medium offers strong selectivity against competing flora while allowing target Salmonella to multiply effectively during the secondary enrichment step.
Selective Enrichment Specialist
🔬 Product Overview
MKTTn Broth Base is formulated for the selective enrichment of Salmonella spp. from samples containing mixed microbial populations. It is especially valuable where samples contain high levels of competing background flora, such as meat, poultry, egg products, milk powder, feed materials, and environmental swabs.
The complete medium is prepared by supplementing the dehydrated base with iodine-potassium iodide solution to generate tetrathionate in situ, together with novobiocin to strengthen selectivity. This combination enhances suppression of organisms such as Proteus, Pseudomonas, and Citrobacter, while supporting multiplication of target Salmonella.
MKTTn is widely used as a second selective enrichment step following pre-enrichment, prior to plating on selective isolation agars such as XLD and other confirmatory media.
⚗️ Principle of the Medium
MKTTn uses a multi-component selectivity system to suppress competing flora while maintaining recovery of Salmonella:
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Tetrathionate generated in situ
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Inhibition of coliform competitors
Brilliant green + ox bile
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Additional suppression of Gram-positive and selected Gram-negative flora
Novobiocin
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Stronger inhibition of Proteus, Pseudomonas, Citrobacter
🧫 Applications
Food Testing
Selective enrichment of Salmonella from meat, poultry, egg products, milk powder, spices, and processed foods.
Feed Microbiology
Useful for recovery of Salmonella from animal feed materials and related agricultural matrices.
Environmental Monitoring
Suitable for environmental swabs and process hygiene samples where Salmonella screening is required.
📋 ISO-Style Workflow Support
Used as a selective enrichment step following non-selective pre-enrichment in buffered peptone water.
📊 Key Features
Generated in situ to suppress coliform competitors.
Improves inhibition of Proteus, Pseudomonas, and Citrobacter.
Calcium carbonate helps counter acidification by competing flora.
Well suited to matrices with heavy microbial background.
🧪 Composition (per litre, complete medium basis)
Preparation
- Suspend 79.7395 g of dehydrated MKTTn base in 1 litre purified water.
- Heat with agitation and boil for 5–10 minutes until completely dissolved.
- Do not autoclave.
- Cool to below 45 °C.
- Aseptically add:
- 20 mL/L iodine-potassium iodide solution
- 40 mg/L novobiocin supplement, filter sterilized
- Mix thoroughly and distribute into sterile tubes or bottles as required.
- Use the completed broth on the same day after supplement addition.
💡 Typical Workflow
Pre-enrich sample in buffered peptone water for 16–20 h.
Transfer 0.1 mL or 1 mL into 10 mL MKTTn.
Incubate at 41.5 ± 1 °C for 24 ± 3 h.
Plate onto XLD and a second selective isolation agar.
📋 Technical Specifications
| Product Name | Mueller Kauffmann Tetrathionate Novobiocin Broth Base |
| Short Name | MKTTn Broth Base |
| Catalogue Number | AS-1301 |
| Medium Type | Selective enrichment broth base |
| Primary Use | Enrichment of Salmonella spp. |
| Supplement Requirement | Iodine-iodide solution + novobiocin |
| Final pH | 8.2 ± 0.2 at 25 °C |
| Incubation | 41.5 ± 1 °C for 24 ± 3 h |
| Pre-Enrichment Step | Typically after BPW pre-enrichment |
| HS Code | 3821.00.00 |
🌡️ Incubation Notes
- ✓ Incubate at 41.5 ± 1 °C
- ✓ Typical duration: 24 ± 3 h
- ✓ Use after non-selective pre-enrichment
- ✓ Subculture onto selective agars after enrichment
✅ Selectivity Advantages
- ✓ Good performance with high-background samples
- ✓ Enhanced suppression of competing Enterobacteriaceae-like flora
- ✓ Suitable as one branch of dual selective enrichment strategy
- ✓ Supports routine food and environmental microbiology screening
❄️ Storage & Handling
- ✓ Base medium without supplements: 2–8 °C up to 1 month
- ✓ Completed broth with iodine + novobiocin: use the same day
- ✓ Do not autoclave the finished medium
- ✓ Prepare supplements aseptically immediately before use
📄 Available Documentation
🧬 Related Salmonella Testing Products
Complementary Enrichment & Isolation Media
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