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Letheen Broth, Modified | Neutralizing Medium for Antimicrobial Testing | AS‑1271
$43.00 AUD
Documentation
AuSaMicS Life Science • Neutralising / Cosmetics Microbiology
Letheen Broth, Modified
Lecithin + Polysorbate 80 Neutralising Enrichment Broth
FDA BAM-validated medium for microbiological examination of cosmetics and non-sterile pharmaceuticals. Dual neutralising system eliminates QAC and phenolic disinfectant carryover for reliable contamination detection.
AS-1271
pH 7.2 ± 0.2
✓ Australian Stock
🧴 Cosmetics & Pharma QC
FDA BAM • ISO 21149
🚀 Same-Day Dispatch: Melbourne Stock
🧪 Regulatory Grade: FDA BAM & ISO compliant
🌿 Dual Neutraliser: Lecithin + Tween 80
🏆 Cosmetics Microbiology Specialist
🧴 FDA BAM Validated — Cosmetics testing
💊 Pharma QC Ready — Non-sterile products
🧫 Broad Spectrum — Bacteria, yeast, mould
📋 Full Documentation — COA + SDS + TDS
⚡ Fast Supply — Ships within 24h
ISO 21149 • ISO 21150 • ISO 18415
Cosmetics & Pharmaceutical Regulatory Compliance
🔬 Mechanism of Action & Neutralisation Chemistry
The term "Letheen" is derived from Lecithin and Tween — reflecting the two active neutralising agents that give this medium its name. The dual system works synergistically:
Lecithin (Soya)
Phospholipid that neutralises quaternary ammonium compounds (QACs) and cationic surfactants via electrostatic binding, preventing carryover inhibition
Phospholipid that neutralises quaternary ammonium compounds (QACs) and cationic surfactants via electrostatic binding, preventing carryover inhibition
Polysorbate 80 (Tween® 80)
Non-ionic surfactant that neutralises phenolic disinfectants, hexachlorophene, and other preservatives via micellar sequestration
Non-ionic surfactant that neutralises phenolic disinfectants, hexachlorophene, and other preservatives via micellar sequestration
Cosmetic / Pharmaceutical Sample (with preservatives/disinfectants)
↓ (Dilution into Letheen Broth, Modified)
Lecithin → Binds & inactivates QACs / cationic biocides
Polysorbate 80 → Sequesters phenolics / hexachlorophene
↓
Viable microorganism recovery without false-negative inhibition
↓ (Dilution into Letheen Broth, Modified)
Lecithin → Binds & inactivates QACs / cationic biocides
Polysorbate 80 → Sequesters phenolics / hexachlorophene
↓
Viable microorganism recovery without false-negative inhibition
Why this matters: Residual preservatives from cosmetic formulations cause false-negative results. Letheen Broth Modified eliminates this interference, ensuring regulatory-compliant microbial counts.
🧪 Detailed Ingredients Table
📊 Comparative Media for Cosmetics & Disinfectant Testing
⚖️ Structured Pros & Cons Analysis
✅ Advantages
- Dual neutralisation — covers the broadest range of common cosmetic preservatives
- FDA BAM compliant — regulatory acceptance in global cosmetics testing
- ISO 21149 / ISO 21150 basis — accepted for pharmaceutical and cosmetics QC audits
- Broad spectrum growth support — recovers bacteria, yeast, and mould
- Eliminates false-negatives — critical for contaminated lot release decisions
- Compatible with surface sampling — used with swabs for environmental monitoring
⚠️ Limitations
- Slight opalescence — normal due to lecithin; may obscure faint turbidity in low-contamination samples
- Not for halogen neutralisation — chlorine/iodine require addition of sodium thiosulfate
- No selectivity — all organisms grow; requires plate subculture for identification
- Tween 80 may promote yeast lipolysis — can affect colonial morphology in some yeasts
- Not a sterility test medium — USP/EP sterility testing requires specific pharmacopoeial media
🧬 Regulatory & Research Applications
🧴 Cosmetics Microbiology
FDA BAM-recommended enrichment broth for the microbiological examination of cosmetic products including lotions, creams, shampoos, and makeup. Validated per ISO 21149:2017 for enumeration of aerobic mesophilic bacteria.
💊 Pharmaceutical QC
Suitable enrichment broth for the microbiological examination of non-sterile pharmaceutical products. Identified in the FDA BAM as appropriate for identification of contaminants in preserved pharmaceutical preparations.
🧹 Disinfectant Efficacy Testing
Used in AOAC and ISO 21150:2015 methods for determining the bactericidal activity of quaternary ammonium compounds and other chemical disinfectants. Essential for validating surface disinfection efficacy.
🌿 Environmental Surface Sampling
Pre-filled in environmental monitoring swabs for surface sampling in GMP manufacturing environments. Recovers organisms from surfaces treated with QAC-based sanitisers, preventing false-negative results in environmental monitoring programmes.
Additional Specialist Applications:
- Phenol Coefficient Testing: AOAC method for cationic surface-active materials
- Sanitiser Challenge Testing: Evaluating cleaning product efficacy in food processing
- Personal Care QC: Sunscreens, antiperspirants, oral care products
- Medical Device Testing: Surface bioburden monitoring on cleaned devices
- Preservative Challenge Studies: ISO 11930 efficacy evaluation support
- GMP Environmental Monitoring: ISO 21148 sampling programmes
💡 Protocol Guidelines
Preparation:
Suspend 38 g/L in distilled water. Autoclave 121°C / 15 min.
Suspend 38 g/L in distilled water. Autoclave 121°C / 15 min.
Inoculation:
1:10 dilution of sample; incubate 30–35°C for 48–72 h
1:10 dilution of sample; incubate 30–35°C for 48–72 h
Appearance (ready):
Slightly opalescent, light to medium amber; slight precipitate normal
Slightly opalescent, light to medium amber; slight precipitate normal
Subculture:
Turbid cultures onto Letheen Agar Modified or TSYA for colony counts
Turbid cultures onto Letheen Agar Modified or TSYA for colony counts
📋 Technical Specifications
| Catalogue Number | AS-1271 |
| Common Name | Letheen Broth, Modified |
| Synonyms | Modified Letheen Broth; Letheen Broth Base Modified + Tween |
| pH (25°C) | 7.2 ± 0.2 |
| Typical Yield | ~38 g/L (approx. 26 L per 1 kg) |
| Appearance (powder) | Cream to light beige homogeneous powder |
| Appearance (prepared) | Slightly opalescent, light–medium amber; slight precipitate |
| Sterilisation | Autoclave 121°C, 15 minutes |
| Incubation (aerobic bacteria) | 30–35°C, 48–72 hours |
| Incubation (yeast & mould) | 20–25°C, 5–7 days |
| Storage | 15–25°C, dry, away from light |
| Available Sizes | 100 g, 500 g, 5 kg |
| HS Code | 3821.00.00 |
📜 Regulatory & Standards Compliance
- ✓ FDA BAM — Bacteriological Analytical Manual (Cosmetics)
- ✓ ISO 21149:2017 — Enumeration & Detection, Aerobic Mesophilic Bacteria
- ✓ ISO 21150:2015 — Detection of Escherichia coli
- ✓ ISO 18415:2017 — Detection of Specified & Non-Specified Microorganisms
- ✓ ISO 21148 — General Instructions for Microbiological Examination
- ✓ AOAC — Official Methods of Analysis (QAC testing)
🧫 Quality Control Organisms
| Organism | ATCC | Expected Result |
|---|---|---|
| Staphylococcus aureus | 6538 | Growth ✓ |
| Escherichia coli | 8739 | Growth ✓ |
| Pseudomonas aeruginosa | 9027 | Growth ✓ |
| Candida albicans | 10231 | Growth ✓ |
| Aspergillus brasiliensis | 16404 | Growth ✓ |
🔄 Cross-Reference / Equivalent Products
| Supplier | Product Name | Cat. No. |
|---|---|---|
| Oxoid | Letheen Broth, Modified | CM0862 |
| BD Difco | Letheen Broth, Modified | 219395 |
| Merck / Millipore | GranuCult® Letheen Broth Base Modified | 110405 |
| HiMedia | Letheen Broth, Modified | M976 |
AuSaMicS AS-1271 is manufactured in Australia — same-week dispatch, local COA/SDS, no import delays
✅ Quality Assurance
- ✓ pH Verified: 7.2 ± 0.2 per lot
- ✓ Growth Promotion: All 5 QC organisms per batch
- ✓ Neutralisation Efficacy: QAC + phenolic challenge tested
- ✓ Sterility: Pre-release sterility check per lot
- ✓ COA Issued: Certificate of Analysis with every order
🧫 Complete Cosmetics & Disinfectant Testing System
Companion Neutralising & Plating Media
Selective & Confirmation Media
Need Cosmetics Microbiology Protocol Support?
Our microbiologists can advise on ISO 21149 / FDA BAM testing workflows and media selection for your specific formulations
For laboratory, research, and industrial use only. Not for food, feed, household, cosmetic, therapeutic, or personal use.
AuSaMicS Pty Ltd • ABN: 56 676 640 467 • 31 Longview CT, Thomastown, VIC 3074, Australia
Same-day dispatch • Australian stock • Full documentation included