Product Overview
This TSA Contact Plate is a specialized environmental monitoring tool formulated with lecithin (0.7 g/L) and Tween-80 (5 g/L) — two well-established neutralizing agents that counteract the antimicrobial activity of residual disinfectants on sampled surfaces.
In facilities where surfaces are routinely treated with quaternary ammonium compounds, chlorhexidine, phenolics, alcohols, or other disinfectants, residual chemical activity can carry over onto a monitoring plate and inhibit microbial growth. This produces false-negative results and underestimates the true bioburden. The lecithin and Tween-80 in this medium neutralize those residues, allowing recovered microorganisms to grow and be accurately enumerated.
The 65mm format provides a larger sampling surface area than standard 55mm plates, improving recovery efficiency on uneven or high-traffic surfaces.
Intended Use
- Surface microbial monitoring after disinfection in cleanrooms (ISO Class 5–8 / Grade A–D).
- Environmental monitoring of equipment, walls, floors, and personnel.
- Bioburden checks on packaging materials.
- Hygiene monitoring in pharmaceutical, cosmetic, and food facilities where disinfectant residues are present.
Composition (per Liter)
- Pancreatic Digest of Casein: 15.0 g
- Papain Digest of Soybean Meal: 5.0 g
- Sodium Chloride: 5.0 g
- Agar: 15.0 g
- Tween-80: 5.0 g
- Lecithin: 0.7 g
- Distilled Water: 1,000 mL
- Final pH: 7.3 ± 0.2 at 25°C
Performance Characteristics
- Appearance: Light yellow, convex, smooth surface, free from cracks, visible impurities, and bubbles.
- Physicochemical: pH compliant; gel strength 500–650 g/cm².
- Sterility: No growth after incubation at 20–25°C for 3 days and 30–35°C for 2 days; no significant medium dehydration.
- Water Retention: No visible shrinkage after 4 hours of open exposure in moving air.
- Growth Promotion: Validated for robust growth with typical colony size and morphology for Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Candida albicans, and Aspergillus niger.
Why Lecithin and Tween-80?
- Lecithin neutralizes quaternary ammonium compounds and biguanides.
- Tween-80 (Polysorbate 80) neutralizes phenolics, alcohols, and other surfactants.
Together they form a broad-spectrum neutralizer system that protects the viability of recovered microorganisms and improves the accuracy of environmental monitoring results.
Packaging and Storage
- Format: 65mm × 10 plates per pack.
- Fill Volume: 15–20 mL per plate.
- Packaging: Three-layer vacuum packaging for cleanroom entry.
- Shelf Life: 90 days from date of manufacture.
- Storage: Store at 2–25°C, protected from light. Do not freeze
