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Listeria Selective HiVeg™ Agar (Twin pack)
Intended Use
Recommended for selective isolation and cultivation of Listeria species from food specimens.
Composition**
| Ingredients | g/L |
|---|---|
| Part A | |
| HiVeg™ hydrolysate | 10.000 |
| HiVeg™ peptone | 10.000 |
| Dextrose (Glucose) | 1.000 |
| Sodium chloride | 5.000 |
| Thiaminium dichloride | 0.005 |
| Acriflavin hydrochloride (Trypaflavin) | 0.010 |
| Nalidixic acid | 0.040 |
| Agar | 13.000 |
| Part B | |
| Potassium thiocyanate | 37.500 |
| Final pH (at 25°C) | 7.4±0.2 |
**Formula adjusted, standardized to suit performance parameters
Direction
Suspend 39.0 grams of Part A and 37.5 grams of Part B 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. Mix well and pour into sterile Petri plates.
Principle And Interpretation
Listeria Selective Agar was proposed by Feindt (1) for the cultivation of Listeria species from clinical and non-clinical specimens. Obiger and Schonberg (2) reported the superiority of these media to yield Listeria from mix-infected specimens. Listeria Selective HiVeg™ Agar (Twin pack) is prepared by completely replacing animal based peptone with vegetable peptones to avoid BSE/TSE risks associate with animal peptones. HiVeg™ hydrolysate, HiVeg™ peptone provides essential nutrients. Thiaminium dichloride is the vitamin B source added to improve the growth of Listeria. Thiocyanate and Nalidixic acid inhibits gram-negative bacteria (3,4). Bockemühl (5) reported suppression of Enterococci by combination of selective agents and acridine dyes. The combination of Acriflavin hydrochloride and Nalidixic acid was recommended by Ralovich et al (6) and Kampelmacher and Van Noorle Jansen (7) for the isolation of Listeria. Listeria Enrichment Broth can be further improved by adding Colimycin alongwith Nalidixic acid (8). The mix infected specimen is added directly to Listeria Enrichment HiVeg™ Broth (Twin pack) or subjected to cold enrichment and then cultured on Listeria Selective HiVeg™ Agar (Twin pack). Haemolytic forms can be identified by inoculating Blood Agar Base, HiVeg™ (Infusion Agar, HiVegTM) (MV073).
Type of specimen
Food samples.
Specimen Collection and Handling:
For food samples, follow appropriate techniques for sample collection and processing as per guidelines (9). After use, contaminated materials must be sterilized by autoclaving before discarding.
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 :
- Some organism may show poor growth due to nutritional variation.
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
Part A: Cream to yellow homogeneous free flowing powder Part B: White to cream homogeneous free flowing powder
Gelling
Firm, comparable with 1.3% Agar gel.
Colour and Clarity of prepared medium
Yellow coloured clear to slightly opalescent gel forms in Petri plates.
Reaction
Reaction of medium (3.9% w/v Part A + 3.75% w/v Part B) at 25°C. pH: 7.4±0.2
pH
7.20-7.60
Cultural Response
Cultural characteristics observed in presence of 10% Carbon dioxide (CO2) after an incubation at 35-37°C for 48 hours.
| Organism | Inoculum (CFU) | Growth | Recovery |
|---|---|---|---|
| Enterococcus faecalis ATCC 29212 (00087*) | 50-100 | none-poor | <=10% |
| Escherichia coli ATCC 25922 (00013*) | >=104 | inhibited | 0% |
| Listeria innocua ATCC 33090 (00017*) | 50-100 | luxuriant | >=50% |
| Listeria ivanovii subsp. ivanovii ATCC 19119 (00018*) | 50-100 | luxuriant | >=50% |
| Listeria monocytogenes ATCC 19112 | 50-100 | luxuriant | >=50% |
| Listeria monocytogenes ATCC 19118 | 50-100 | luxuriant | >=50% |
Key: *Corresponding WDCM numbers.
Storage and Shelf Life
Store dehydrated 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 clinical sample must be decontaminated and disposed of in accordance with current laboratory techniques (10,11).
| Product Name | Listeria Selective HiVeg™ Agar (Twin pack) |
|---|---|
| SKU | MV567 |
| Product Type | HiVeg™ |
| Physical Form | Powder |
| Origin | Animal Free (Veg) |
| Packaging type | HDPE |
| References | 1.Feindt E., 1972, Inuug. Diss., Würzburg. 2.Obiger G. and Schonberg A., 1973, Fleischwirtschaft, 10:1450. 3.Lebnert C., 1964, Arch. Exp. Vet. Med.,8:891 and 1247. 4.Beerens H. and Tahon-Castel M.M., 1966, Ann. Inst. Pasteur, 111:90. 5.Bockemühl J.,Seeliger H.P.R. and Kathke R., 1971, J. Med. Microbiol. Imm. 157:84. 6.Ralorich B., et al, 1971, Zbl. Bakt. I.Orig., 216:88. 7.Kampelmacher E.H. and Van Noorle-Jansen L.M., 1972, Zbl. Bakt. J.Orig.,221:139. 8.Grey M.L. et al, 1948, J. Bact., 55:471. |
| Customized Product Available | No |












