Plot No. C40, Road No. 21Y, MIDC, Wagle Industrial Estate,
Thane(W)-400604, MH, India.
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Intended Use
Recommended for selective isolation and enumeration of Clostridium perfringens in food
Composition
| Ingredients | Gms / Litre |
|---|---|
| Tryptone | 15.000 |
| Soya peptone | 5.000 |
| Yeast extract | 5.000 |
| HL extract # | 7.000 |
| Ferric ammonium citrate | 1.000 |
| Sodium metabisulphite | 1.000 |
| Tris buffer | 1.500 |
| Agar | 15.000 |
| Final pH (at 25°C) | 7.3±0.2 |
**Formula adjusted, standardized to suit performance parameters
# Equivalent to Liver extract
Directions
Either streak, inoculate or surface spread the test inoculum (50-100 CFU) aseptically on the plate.
Principle And Interpretation
Clostridial species are one of the major causes of food poisoning/ gastrointestinal illnesses. They are gram-positive spore-forming rods that occur naturally in the soil (1). Foods commonly contaminated with Clostridium perfringens include meat, meat pies, poultry, stews and gravy. Among the family are: Clostridium botulinum which produces one of the most potent toxins in existence; Clostridium tetani, causative agent of tetanus; and C. perfringens commonly found in wound infections and diarrhoea cases. The use of toxins to damage the host is a method deployed by many bacterial pathogens. The major virulence factor of C. perfringens is the CPE enterotoxin, which is secreted upon invasion of the host gut, and contributes to food poisoning and other gastrointestinal illnesses (1).
Perfringens Agar (O.P.S.P.) is based on the formula developed by Handford (2) and is used as a selective medium for isolation and enumeration of C. perfringens in foods (3).
Tryptone, yeast extract, Soya peptone and HL extract supply most of the essential nitrogenous nutrients, vitamin B complex and trace ingredients for the growth of C.perfringens. Sodium metabisulphite and ferric ammonium citrate are used as indicators of sulphate reduction by C. perfringens, which produces black colonies. Tris buffer helps in maintaining buffering action. The antibiotics sulphadiazine, oleandomycin and polymyxin B make the medium highly selective inhibiting sulphite-reducing bacteria other than C. perfringens such as Salmonella, Bacillus species, Proteus species, Staphylococci etc.
Prepare 10 fold dilution of a 10% homogenate of the food sample in 0.1% Peptone Water (M028). Viable counts of C.perfringens bacilli or spores are obtained by plating 0.1 ml of different dilutions onto duplicate plates of blood agar containing 5 mg/lit of gentamicin/lt. Incubate at 37°C for 18-24 hours in two sets, one anaerobically and another aerobically. Alternatively incorporate 1 ml of the dilution into 25 ml of molten and cooled Perfringens Agar (O.P.S.P.) containing supplements. Incubate anaerobically for 18-24 hours at 37°C. Perfringens Agar with supplements gives high degree of selectivity and specificity.
Type of specimen
Food samples.
Specimen Collection and Handling
Prepare 10 fold dilution of a 10% homogenate of the food sample in 0.1% Peptone Water (M028). Viable counts of C. perfringens bacilli or spores are obtained by plating 0.1 ml of different dilutions onto duplicate plates of blood agar containing 5 mg/lit of gentamicin/lt. Incubate at 37°C for 18-24 hours in two sets, one anaerobically and another aerobically. Alternatively incorporate 1 ml of the dilution into 25 ml of molten and cooled Perfringens Agar (O.P.S.P.) containing supplements. Incubate anaerobically for 18-24 hours at 37°C. Perfringens Agar with supplements gives high degree of selectivity and specificity.
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 guidleines should be followed while handling specimens. Saftey guidelines may be referred in individual safety data sheets
Limitations
- Further biochemical and serological tests must be carried out for further 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
Sterile Perfringens Agar Plate in 90 mm disposable plates.
Colour of medium
Amber coloured medium
Quantity of medium
25 ml of medium in 90 mm disposable plates.
Reaction
7.10-7.50
Sterility Test
Passes release criteria
Cultural Response
Cultural characteristics observed after an incubation at 35-37°C for 18-48 hours
| Organism | Inoculum (CFU) | Growth | Recovery | Colour of colony |
|---|---|---|---|---|
| Bacillus subtilis subsp. spizizenii ATCC 6633 (00003*) | >=10⁴ | inhibited | 0% | |
| Clostridium bifermentans ATCC 17837 | >=10⁴ | inhibited | 0% | |
| Clostridium butyricum ATCC 13732 | >=10⁴ | inhibited | 0% | |
| Clostridium perfringens ATCC 12924 | 50-100 | luxuriant | >=50% | black |
| Enterococcus faecalis ATCC 29212 (00087*) | 50-100 | none-poor | <=10% | white, if any |
| Proteus vulgaris ATCC 13315 | >=10⁴ | inhibited | 0% | |
| Salmonella Typhi ATCC 6539 | >=10⁴ | inhibited | 0% | |
| Staphylococcus aureus subsp. aureus ATCC 25923 (00034*) | >=10⁴ | inhibited | 0% |
Key: *Corresponding WDCM numbers.
Storage and Shelf Life
On receipt store between 2-8°C Use before expiry date on the label.
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 (4,5).
| Product Name | Perfringens Agar Plate |
|---|---|
| SKU | MP579 |
| Customized Product Available | No |
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