Ready-to-use media
Tryptone Soya Agar (TSA) with Neutralizings. Double Wrapped. Irradiated
General purpose medium for isolation and culture of microorganisms with neutralisers.
- Cat. No.
- LC-840
- Category
- Ready-to-use media
- Format
- 20 plates, 90 mm
- ISO 17025 quality control
- Yes
- Storage
- 2 to 14 °C
- Minimum guaranteed shelf life
- 1 month
TSA is a widely used medium containing two peptones which support the growth of a wide variety of organisms, even that of very fastidious ones such as Neisseria, Listeria, Brucella, etc. It is frequently used for routine diagnostic purposes due to its reliability and its easily reproducible results.
Key features
Applications
Non-selective enumeration of aerobes.
Industry
Environmental monitoring, water.
Presentation
20 irradiated plates, 90 mm, double wrapping, with 21 ± 2 mL.
Packaging
1 box with 2 cellophane bags (double wrapping) with 10 plates/bag. Every pack exhibits an irradiation indicator (8-14 kGy).
Description and technique
Description
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.
- The 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.
This medium is also well suited for air environmental sampling (total compatibility with most commercially available air samplers) or for other types of environmental sampling (e.g. fingers or gloves of operators, swab streaking).
Spread the plates by streaking methodology or by spiral method.
The inoculated plates are incubated at 30-35 °C for 24-72 h (bacteria) and 3-5 days for fungi (yeasts and molds). Examined daily.
(Incubation times greater than those mentioned above or different incubation temperatures may be required depending on the sample, on the specifications. This medium can be inoculated directly or after enrichment broth.)
After incubation, enumerate all the colonies that have appeared onto the surface of the 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 incubation time and temperature.
Presentation
| Presentation | 20 irradiated plates, 90 mm, double wrapping |
|---|---|
| Filling | 21 ± 2 mL |
| Packaging | 1 box with 2 cellophane bags (double wrapping) with 10 plates/bag. Every pack exhibits an irradiation indicator (8-14 kGy). |
Composition
| Ingredient | g/L |
|---|---|
| Peptone from casein | 15.0 |
| Soya peptone | 5.00 |
| Sodium chloride | 5.00 |
| Histidine | 1.00 |
| Lecithin | 0.70 |
| Polysorbate 80 | 5.00 |
| Sodium thiosulfate | 0.50 |
| Agar | 15.0 |
Quality control
Physical/chemical control
| Color | Straw-coloured yellow |
|---|---|
| pH | 7.3 ± 0.2 at 25 °C |
Microbiological control
Growth Promotion Test according to harmonized pharmacopoeial monographs and test methods and ISO 11133:2014.
Inoculate: practical range 100 ± 20 CFU; min. 50 CFU (productivity) / 10⁴-10⁶ (selectivity).
Aerobiosis. Incubation at 30-35 °C. Read after 18-24 h to 72 h for bacteria and 3-5 days for fungi.
| Microorganism | Growth |
|---|---|
| Escherichia coliATCC 8739, WDCM 00012 | Good (≥ 70%) |
| Staphylococcus aureusATCC 6538, WDCM 00032 | Good (≥ 70%) |
| Bacillus subtilisATCC 6633, WDCM 00003 | Good (≥ 70%) |
| Candida albicansATCC 10231, WDCM 00054 | Poor to good |
| Aspergillus brasiliensisATCC 16404, WDCM 00053 | Good (≥ 70%) |
| Ps. aeruginosaATCC 9027, WDCM 00026 | Good (≥ 70%) |
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 Media. CRC Press, Inc. London.
- COLIPA (1997) Guidelines on Microbial Quality Management (MQM). Brussels.
- DOWNES, F.P. & K. ITO (2001) Compendium of Methods for the Microbiological Examination of Food, 4th ed, ASM, Washington D.C.
- EUROPEAN PHARMACOPOEIA 8.0 (2014) 8th ed. § 2.6.13. Microbiological examination of non-sterile products: Test for specified microorganisms. Harmonised Method. EDQM. Council of Europe. Strasbourg.
- FDA (Food and Drug Administration) (1998) Bacteriological Analytical Manual. 8th ed. Rev. A. AOAC International. Gaithersburg. MD.
- HORWITZ, W. (2000) Official Methods of Analysis of AOAC INTERNATIONAL, 17th ed. Gaithersburg, MD. USA.
- ISO 9308-1 Standard (2000) Water Quality. Detection and enumeration of E. coli and coliform bacteria. Membrane filtration method.
- ISO 11133:2014/Amd 1:2018. Microbiology of food, animal feed and water. Preparation, production, storage and performance testing of culture media.
- ISO 16212 Standard (2017) Cosmetics - Microbiology - Enumeration of yeast and mould.
- 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.
- ISO/TS 22964 (2006) Milk and milk products - Detection of Enterobacter sakazakii.
- PASCUAL ANDERSON, Mª R. (1992) Microbiología Alimentaria. Díaz de Santos S.A., Madrid.
- USP 33 - NF 28 (2011) <62> Microbiological examination of non-sterile products: Test for specified microorganisms. Harmonised Method. USP Corp. Inc. Rockville. MD. USA.
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The product
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