R-2A 琼脂

R-2A Agar is a low-nutrient culture medium formulated for the cultivation and enumeration of heterotrophic bacteria from water and other oligotrophic environments; developed by Reasoner and Geldreich for bacteriological counts in treated drinking water, it favors recovery of stressed, injured, or chlorine-tolerant organisms that may be inhibited on nutrient-rich media. Its reduced nutrient content minimizes overgrowth by fast-growing species, enabling slow-growing or debilitated bacteria to recover, especially with extended incubation and, if needed, lower temperatures; this yields higher recovery rates in environmentally stressed samples. It is widely used for routine microbiological monitoring of water types such as purified water, highly purified water, and water for injection. The formulation includes casein hydrolysate and peptone as nitrogen and carbon sources, yeast extract for vitamins and trace elements, soluble starch to absorb inhibitory by-products, sodium pyruvate to support resuscitation, magnesium sulphate for divalent cations, and potassium phosphate as a buffer and phosphate source, with agar as the solidifying agent. R-2A Agar supports both spread and pour plate techniques, with water samples collected and stored per standard procedures, tested promptly and refrigerated to minimize population changes. Plates are incubated for 5–7 days at 20–35 °C, and results are expressed as colony-forming units per volume based on dilution with a target count of 30–300 colonies per plate.

用于采用较长培养期的水样异养菌平板计数。

Features:

• High-Quality Standards: NutriSelect^® Plus powdered culture media are made from carefully selected raw materials, ensuring consistent quality.
• Wide Range of Applications: Suitable for various microbiological needs, including academic research, food and beverage testing, and pharmaceutical applications.
• Regulatory Compliance: Products meet industry standards and are compliant with ISO 9001 quality assurance.
• Innovative Formulations: Includes novel media types such as non-animal-derived alternatives, synthetically defined media, and chromogenic media.

Benefits:

• Convenience and Safety: Easy-to-use powdered format with minimal clumping and excellent solubility, even in warm or humid conditions.
• Sustainability: Reduced risks associated with fine dust and toxic substance inhalation, ensuring a safer work environment.
• Extended Shelf Life: Products have a prolonged shelf life of up to five years.
• High Reproducibility: Ensures consistent results across batches, exceeding regulatory demands.
• Comprehensive Portfolio: A vast selection of over 350 products tailored to meet diverse microbiological testing needs.

Suspend 18.12 g in 1 litre distilled water. Boil to dissolve the medium completely. Sterilize by autoclaving at 121°C for 15 minutes.

We offer two media types: the superior granulated GranuCult^® and the cost-efficient powdered NutriSelect^® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany

NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany