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Tergitol-7 HiVeg™ Agar Base
Intended Use
Recommended for selective enumeration and identification of coliform organisms.
Composition
| Ingredients | g/L |
|---|---|
| HiVeg® peptone No. 3 | 5.000 |
| Yeast extract | 3.000 |
| Lactose | 10.000 |
| Tergitol 7 (Sodium heptadecyl sulphate) | 0.100 |
| Bromo thymol blue | 0.025 |
| Agar | 15.000 |
| Final pH (at 25°C) | 6.9±0.2 |
**Formula adjusted, standardized to suit performance parameters
Directions
Suspend 33.13 grams in 1000 ml purified/distilled water. Heat to boiling to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 45-50°C. Aseptically add 3 ml of TTC Solution 1% (FD057), if desired. Mix well and pour into sterile Petri plates.
Principle And Interpretation
Tergitol-7 Agar was originally designed by Chapman (1) and later on modified by incorporating 2,3,5-Triphenyl Tetrazolium Chloride (TTC) into the medium. This medium is selective and differential used for the detection and enumeration of coliform organisms. Pollard (2) has reported the selective bactericidal property of sodium heptadecyl sulphate (Tergitol-7). Kulp et al (3) corroborated the use of Tergitol-7 Agar with TTC in routine analysis of water and Mossel (4) used this medium for the examination of food materials.
Tergitol-7 HiVeg® Agar Base is prepared by completely replacing animal based peptone with vegetable peptones to avoid BSE/TSE risks associate with animal peptones. HiVeg® peptone No. 3 and yeast extract serve as sources of carbon, nitrogen and other essential nutrients including vitamin B complex.
Sodium heptadecyl sulphate (Tergitol-7) inhibits gram-positive bacteria and Proteus swarming and yields better recovery of coliforms. Bromo thymol blue is the pH indicator. Lactose fermenting organisms form yellow colonies with yellow zones while Klebsiella and Enterobacter form greenish yellow colonies. Lactose non-fermenters produce blue colonies. TTC is reduced by the bacterial cell except Escherichia coli and Klebsiella aerogenes to form formazan, a red coloured insoluble complex, thereby producing red coloured colonies.
Filter the specimen to be analyzed through two membranes. Place the membrane upon two TTC Tergitol Agar plates. Incubate one plate at 37°C for 24 hours (total coliforms) and the other at 44°C for 18-24 hours (faecal coliforms). The yellow colonies with deep yellow halo after incubation at 44°C should be identified as faecal coliform bacteria.
Type of specimen
Water samples
Specimen Collection and Handling
Filter the specimen to be analyzed through two membranes. Place the membrane upon two TTC Tergitol Agar plates. Incubate one plate at 37°C for 24 hours (total coliforms) and the other at 44°C for 18-24 hours (faecal coliforms). The yellow colonies with deep yellow halo after incubation at 44°C should be identified as faecal coliform bacteria.
Warning and Precautions
Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling specimens. Safety guidelines may be referred in individual safety data sheets.
Limitations
- Further biochemical and serological tests must be carried out for complete identification.
Performance and Evaluation
Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.
Quality Control
Appearance
Cream to light green homogeneous free flowing powder
Gelling
Firm, comparable with 1.5% Agar gel
Colour and Clarity of prepared medium
Green coloured clear to slightly opalescent gel forms in Petri plates
Reaction
Reaction of 3.31% w/v aqueous solution at 25°C. pH: 6.9±0.2
pH
6.70-7.10
Cultural Response
Cultural characteristics observed after an incubation at 35-37°C for 18-48 hours with added TTC Solution 1% (FD057).
| Organism | Inoculum (CFU) | Growth | Recovery | Colour of colony/ medium |
|---|---|---|---|---|
| # Klebsiella aerogenes ATCC 13048 (00175*) | 50-100 | luxuriant | >=50% | Reddish brown |
| Escherichia coli ATCC 25922 (00013*) | 50-100 | good-luxuriant | >=50% | yellow with red centre |
| Proteus mirabilis ATCC 25933 | 50-100 | good | 40-50% | red with bluish zone |
| Pseudomonas aeruginosa ATCC 27853 (00025*) | 50-100 | good | 40-50% | red with bluish zone |
| Salmonella Typhimurium ATCC 14028 (00031*) | 50-100 | luxuriant | >=50% | red with bluish zone |
| Staphylococcus aureus subsp. aureus ATCC 25923 (00034*) | >=104 | inhibited | 0% | |
| Shigella flexneri ATCC 12022 (00126*) | 50-100 | good-luxuriant | >=50% | red with bluish zone |
Key: (*) Corresponding WDCM numbers. (#) Formerly known as Enterobacter aerogenes
Storage and Shelf Life
Store between 10-30°C in a tightly closed container and the prepared medium at 2-8°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition. Seal the container tightly after use. Product performance is best if used within stated expiry period.
Disposal
User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with sample must be decontaminated and disposed of in accordance with current laboratory techniques (5,6).
| Product Name | Tergitol-7 HiVeg™ Agar Base |
|---|---|
| SKU | MV616 |
| Product Type | HiVeg™ |
| Physical Form | Powder |
| Origin | Animal Free (Veg) |
| Packaging type | HDPE |
| References | 1.Chapman G.H., 1947, J. Bact., 53:504. 2.Pollard A.L., 1946, Science, 103:758. 3.Kulp W., Mascoli C. and Tavshanjian O., 1953, Am. J. Public Health, 43:11 4.Mossel D.A.A., 1962, J. Appl. Bact., 25:20. |
| Customized Product Available | No |






