Ready-to-use media
Dey-Engley Neutralizing Broth ISO
Liquid medium for enrichment cultures in cosmetics, according to ISO standards.
- Cat. No.
- LC-5077
- Category
- Ready-to-use media
- Format
- 10 x 100 mL flasks
- ISO 17025 quality control
- Yes
- Storage
- 8 to 25 °C
- Minimum guaranteed shelf life
- 6 months
- Also available
- Dehydrated medium, 1 format (LC-2003)
Initially, Dey & Engley developed this medium in 1983 to recover chemically damaged staphylococci. At present its use has expanded to verify several aspects in the application of disinfectants and preservatives.
Key features
Applications
Enrichment with neutralizers (general use).
Industry
Cosmetics.
Presentation
10 prepared bottles, 125 mL, with 100 ± 3 mL.
Packaging
1 box with 10 bottles 125 mL. Injectable cap: plastic screw inner cap. The use of syringe needles with a diameter greater than 0.8 mm is not recommended.
Description and technique
The present formulation incorporates neutralizing substances for almost all the active products used as preservatives in cosmetic production. Lecithin neutralizes quaternary ammonium compounds (QACs); polysorbate acts on phenolics and formalin; thioglycolate neutralizes the organic mercurial compounds; thiosulfate-sulfite inactivates halogen compounds and lecithin + polysorbate neutralizes ethanol and other alcoholic compounds.
The ISO Standards give this medium as an alternative for culture enrichment in the detection of aerobic mesophilic bacteria (ISO 21149), in the detection of Escherichia coli (ISO 21150) and for verifying the presence of Pseudomonas aeruginosa (ISO 22717) and Staphylococcus aureus (ISO 22718).
Inoculate according to final purpose, samples and validated methods.
When the product is water-soluble, a suitable sample (1 g or 1 mL) is transferred to 9 mL of D/E Neutralizing Broth. If the product is not water-soluble, it must first be dissolved with polysorbate 80 or another emulsifier product.
The D/E Neutralizing Broth with the sample is then incubated at 32.5 ± 2.5 °C for at least 20 hours and no more than 72 hours before subculturing on a suitable solid medium for isolation of colonies.
Presentation
| Presentation | 10 prepared bottles, 125 mL |
|---|---|
| Filling | 100 ± 3 mL |
| Packaging | 1 box with 10 bottles 125 mL. Injectable cap: plastic screw inner cap. The use of syringe needles with a diameter greater than 0.8 mm is not recommended. |
Composition
| Ingredient | g/L |
|---|---|
| Tryptone | 5.00 |
| Yeast extract | 2.50 |
| Dextrose | 10.00 |
| Lecithin | 7.00 |
| Polysorbate 80 | 5.00 |
| Sodium thiosulphate | 6.00 |
| Sodium bisulfite | 2.50 |
| Sodium thioglycollate | 1.00 |
| Bromcresol purple | 0.02 |
Quality control
Physical/chemical control
| Color | Violet |
|---|---|
| pH | 7.6 ± 0.2 at 25 °C |
Microbiological control
Inoculate with 10³-10⁴ CFU (qualitative).
Aerobiosis. Incubation at 30-35 °C. Reading at 24-48 h.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 8739, WDCM 00012 | Good. Recovery in D/E Neutralizing Agar |
| Bacillus subtilisATCC 6633, WDCM 00003 | Good. Recovery in D/E Neutralizing Agar |
| Staphylococcus aureusATCC 6538, WDCM 00032 | Good. Recovery in D/E Neutralizing Agar |
| Ps. aeruginosaATCC 9027, WDCM 00026 | Good. Recovery in D/E Neutralizing Agar |
| Candida albicansATCC 10231, WDCM 00054 | Good. Recovery in D/E Neutralizing Agar |
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
- ATLAS, R.M. & L.C. PARKS (1993) Handbook of Microbiological Culture Media. CRC Press. Boca Raton. Fla.
- DEY, B.P. & F.B. ENGLEY (1983) Methodology for recovery of chemically treated Staphylococcus aureus with neutralizing medium. Appl. Environm. Microbiol. 453:1533-1537.
- HICKEY, P.J., C.E. BECKELHEIMER & T. PARROW (1992) Microbiological tests for equipment, containers, water and air. In R.T. Marshall (Ed.) Standard Methods for the Examination of Dairy Products. 16th ed. APHA. Washington.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
- ISO 18415 Standard (2017) Cosmetics - Microbiology - Detection of specified and non-specified microorganisms.
- ISO 18416 Standard (2015) Cosmetics - Microbiology - Detection of Candida albicans.
- ISO 21149 Standard (2017) Cosmetics - Microbiology - Enumeration and detection of aerobic mesophilic bacteria.
- ISO 21150 Standard (2015) Cosmetics - Microbiology - Detection of Escherichia coli.
- ISO 22717 Standard (2015) Cosmetics - Microbiology - Detection of Pseudomonas aeruginosa.
- ISO 22718 Standard (2015). Cosmetics - Microbiology - Detection of Staphylococcus aureus.
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.
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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.
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How long does delivery take?
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