Plot No. C40, Road No. 21Y, MIDC, Wagle Industrial Estate, Thane(W)-400604, MH, India
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Intended use
Recommended for the isolation and enumeration of yeasts and moulds from water, dairy and other food products and clinical samples.
Composition
| Ingredients | g / L |
|---|---|
| Potatoes, infusion 200 g # | 4.000 |
| Dextrose (Glucose) | 20.000 |
| Agar | 15.000 |
| Final pH (at 25°C) | 5.6±0.2 |
Formula adjusted, standardized to suit performance parameters
Directions
Either streak, inoculate or surface spread the test inoculum (50-100 CFU) aseptically on the plate.
Principle And Interpretation
Potato Dextrose Agar is recommended by APHA (1) and F.D.A.(2) for plate counts of yeasts and moulds in the examination of foods and dairy products (3). Potato Dextrose Agar is also used for stimulating sporulation, for maintaining stock cultures of certain dermatophytes and for differentiation of typical varieties of dermatophytes on the basis of pigment production(4). It is also recommended by USP (5), BP (6) and EP(3) for growth of fungi. Potato infusion and dextrose promote luxuriant fungal growth.
Type of specimen
Food and dairy samples; Water samples
Specimen Collection and Handling:
For food and dairy samples, follow appropriate techniques for sample collection and processing as per guidelines (1,7).
For water samples, follow appropriate techniques for sample collection, processing as per guidelines and local standards (8).
After use, contaminated materials must be sterilized by autoclaving before discarding.
Warning and Precautions
In Vitro diagnostic use. For professional use only. 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 clinical specimens. Safety guidelines may be referred in individual safety data sheets.
Limitations :
- Individual organisms differ in their growth requirement and may show variable growth patterns on the medium.
- Each lot of the medium has been tested for the organisms specified on the COA. It is recommended to users to validate the medium for any specific microorganism other than mentioned in the COA based on the user's requirement.
- Further serological and biochemical testing is required 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
Sterile Potato Dextrose Agar in 90 mm disposable plates with smooth surface and absence of black particles/cracks/bubbles.
Colour of medium
Yellow coloured medium
Quantity of medium
25 ml of medium in 90 mm disposable plates.
pH
5.40 -5.80
Sterility Check
Passes release criteria
Cultural Response
Cultural characteristics observed after an incubation at 22 - 25°C for 4 - 5 days.
| Organism | Growth | Ascospore formation |
|---|---|---|
| # Aspergillus brasiliensis ATCC 16404 (00053*) | luxuriant | Negative |
| Candida albicans ATCC 10231 (00054*) | luxuriant | Negative |
| Saccharomyces cerevisiae ATCC 9763 (00058*) | luxuriant | Positive |
Key: (#) - Formerly known as Aspergillus niger, (*) - corresponding WDCM numbers
Storage and Shelf Life
On receipt store between 20-30°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 (9,10).
| Product Name | Potato Dextrose Agar Plate |
|---|---|
| SKU | MP096 |
Write Your Own Review
Should I add antibiotics to PDA?
Yes, adding chloramphenicol (25-50 mg/L) or other broad-spectrum antibiotics to PDA is recommended when testing samples with high bacterial loads (cannabis, food, soil, environmental). Antibiotics inhibit bacterial growth that would overgrow and obscure fungal colonies. For cannabis testing, chloramphenicol supplementation is standard practice. Pre-made PDA with antibiotics: order PDA with Chloramphenicol from HiMedia. HiMedia offers M1941 Potato Dextrose Agar w/ Chloramphenicol. Do not add antibiotics when culturing bacteria-fungi interactions.
What is the incubation temperature and time for PDA?
Standard incubation for PDA: 25-28°C (room temperature) for 5-7 days. Specific applications: (1) Cannabis TYMC: 25-28°C for 5-7 days (some states allow 3-5 days), (2) Food mold testing: 25°C for 5 days per AOAC, (3) Pharmaceutical mold testing: 20-25°C for 5-7 days per USP <61>, (4) Clinical mycology: may extend to 14 days for slow-growing pathogenic fungi. Check plates daily after day 3. Prolonged incubation (>7 days) increases contamination risk but may recover fastidious fungi.
Why is yeast and mold testing required for cannabis?
Yeast and mold testing ensures product safety and quality. Concerns: (1) Aspergillus species produce aflatoxins (carcinogenic) and can cause aspergillosis in immunocompromised users, (2) High mold counts indicate poor cultivation/storage practices, (3) Mold growth produces musty odors and off-flavors, (4) Some states require specific Aspergillus testing (A. fumigatus, A. flavus, A. niger, A. terreus) due to health risks. Inhalation of moldy cannabis is particularly dangerous. Most states mandate TYMC testing for all cannabis products before sale.
How is PDA used for cannabis testing?
For cannabis Total Yeast & Mold Count (TYMC): (1) Homogenize 1g cannabis flower in 9mL sterile diluent, (2) Make serial dilutions (10^-1, 10^-2, 10^-3), (3) Plate 0.1mL or 1mL onto PDA with chloramphenicol (25 mg/L to inhibit bacteria), (4) Incubate at 20-25° C for 5-7 days, (5) Count yeast and mold colonies, calculate CFU/g. State limits vary: California <1,000 CFU/g for flower. For concentrates/edibles: stricter limits <100-1,000 CFU/g. PDA is the industry-standard medium for cannabis TYMC testing.
What is Potato Dextrose Agar used for?
Potato Dextrose Agar (PDA) is a general-purpose medium for cultivation of yeasts and molds. Primary uses: (1) Cannabis testing - Total Yeast & Mold Count (TYMC) per state regulations, (2) Food mycology - mold identification and enumeration, (3) Pharmaceutical microbial limits (USP <61>/<62>), (4) Environmental monitoring for fungal contamination, (5) Antifungal susceptibility testing, (6) Fungal culture maintenance. The acidic pH (5.6) and high dextrose content favor fungal growth while inhibiting most bacteria.