Ready-to-use media
Diluent of Beerens
Diluent for examination of cosmetic products with neutralizers.
- Cat. No.
- LC-4038
- Category
- Ready-to-use media
- Formats
- 4 formats
- ISO 17025 quality control
- Yes
- Storage
- 8 to 25 °C
Cosmetic Beeren's Diluent has all the necessary compounds to neutralize most of the chemical agents included in cosmetic products to maintain and preserve them free of microorganisms.
Key features
Applications
Diluent (general use).
Industry
Cosmetics.
Description and technique
Description
It complies with the EU recommendation that states that before any microbiological examination, a treatment to remove all growth inhibitor systems in cosmetics must be performed.
However, this standard also declares that later dilutions must be performed in less aggressive media, that may be considered as an enrichment and revitalization system, and suggests the use of Letheen Broth or Letheen Modified Broth.
The addition of the neutralizing agents TLHTh (Tween 80 - Lecithin - Histidine - Sodium Thiosulphate) may inactivate a variety of disinfectants:
- The combination of lecithin, polysorbate 80 and histidine neutralizes aldehydes and phenolic compounds.
- The combination of lecithin and polysorbate 80 neutralizes the quaternary ammonium compounds.
- Polysorbate 80 neutralizes hexachlorophene and mercurial derivatives.
- Sodium thiosulphate neutralizes halogen compounds.
- Lecithin neutralizes chlorhexidine.
- Histidine neutralizes formaldehyde.
Technique
Collect, dilute and prepare samples and volumes as required according to specifications, directives, official standard regulations and/or expected results. Dispense liquid medium in appropriate containers if the original container is of large volume.
Inoculate aseptically the tubes with the prepared sample or its dilution. Incubation times, temperature and sample volumes may vary depending on the sample, on the specifications.
This medium can be used to inoculate any confirmatory, secondary medium by streaking methodology or by spiral method; after proper incubation, enumerate all the colonies that have appeared onto the surface of the secondary agar.
Each laboratory must evaluate the results according to their specifications.
Calculate total microbial count per mL of sample by multiplying the average number of colonies per plate by the inverse dilution factor if a diluted sample was streaked. Report results as colony forming units (CFU) per mL or g along with enrichment and secondary media used, incubation time and temperature.
Presentation
| Code | Presentation | Filling | Packaging |
|---|---|---|---|
| LC-4038 | 20 tubes, 16 x 113 mm | 9 ± 0.1 mL | 1 box with 20 tubes, 16 x 113 mm glass tubes, ink labelled and metal non-injectable cap. |
| LC-5044 | 10 prepared bottles, 125 mL | 90 ± 3 mL | 1 box with 10 bottles 125 mL. Metal non-injectable cap. |
| LC-5064 | 10 prepared bottles, 125 mL | 100 ± 3 mL | 1 box with 10 bottles 125 mL. Non-injectable cap. |
| LC-5065 | 10 prepared bottles, 125 mL | 45 ± 3 mL |
Composition
| Ingredient | g/L |
|---|---|
| Lecithin | 3.00 |
| Sodium thiosulfate | 5.00 |
| L-histidine | 1.00 |
| Peptone | 1.00 |
| Sodium chloride | 8.50 |
| Dipotassium phosphate | 1.00 |
| Polysorbate 80 | 30.0 mL |
Quality control
Physical/chemical control
| Color | Pale yellow |
|---|---|
| pH | 7 ± 0.2 at 25 °C |
Microbiological control
Prepare tubes / inoculate 10³-10⁴ (productivity) / subculture after holding at 20-25 °C for 45 min to 1 h.
Aerobic. Incubation at 32.5 ± 2 °C, reading after 24-48 h.
| Microorganism | Growth |
|---|---|
| Staphylococcus aureusATCC 6538, WDCM 00032 | Good. Recovery ± 30% T0 (original enumeration) |
| Bacillus subtilisATCC 6633, WDCM 00003 | Good. Recovery ± 30% T0 (original enumeration) |
| Escherichia coliATCC 8739, WDCM 00012 | Good. Recovery ± 30% T0 (original enumeration) |
| Salmonella typhimuriumATCC 14028, WDCM 00031 | Good. Recovery ± 30% T0 (original enumeration) |
| Ps. aeruginosaATCC 9027, WDCM 00026 | Good. Recovery ± 30% T0 (original enumeration) |
| Candida albicansATCC 10231, WDCM 00054 | Good. Recovery ± 30% T0 (original enumeration) |
| Reference media (LC-4038 only) | TSA for bacteria / SDA for fungi |
Sterility control
Incubation 48 hours at 30-35 °C and 48 hours at 20-25 °C: NO GROWTH.
Check at 7 days after incubation in same conditions.
Bibliography
- BEERENS, H., RAMONS, C., LEMAIRE, D. (1976) Rev. Inst. Pasteur. Lyon. 9:127.
- BRIGIDI, P., MATTEUZZI, D. (1982) Il Farmaco Ed. Pr. 37:8:260.
- CEE (1976) Commission des Communautés Européennes. Groupe Spécial des Méthodes de Contrôle Microbiologique des Produits Cosmétiques: Limites Numériques Applicables au Contrôle Officiel de la Qualité Microbiologique des Produits Cosmétiques. XI/405A. ISPRA. 1976.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
Every lot comes with its certificate.
Tracked shipment
Follow your shipment live, from our warehouse to your lab.
Other products in the same category
Frequently asked questions
Can I ask for formats other than those listed?
Yes: custom formats and OEM packs are available on request. Tell us the quantities you need.
How do I see the prices?
Prices are shown after you sign in to the customer area, with your account discount already applied.
How long does delivery take?
We give you the availability with the quote, within 24 hours of your request.