Thioglycollate Fluid Medium without Indicator is a liquid medium used for the cultivation of a broad range of aerobic, anaerobic, and microaerophilic microorganisms. This specific version is formulated without the redox indicator Resazurin, making it ideal for the examination of samples that are naturally colored or turbid, and for applications where the indicator might interfere with the recovery of certain fastidious organisms.
This medium is designed to maintain a low oxidation-reduction potential to support anaerobic growth in standard incubation conditions. The Pancreatic Digest of Casein and Yeast Extract serve as the primary sources of nitrogen, amino acids, and essential B-vitamins. Glucose provides the energy source for microbial metabolism. Sodium Thioglycollate and L-Cystine act as reducing agents that chemically remove molecular oxygen. The inclusion of a small amount of Bacteriological Agar creates a semi-solid environment that helps prevent the rapid diffusion of oxygen into the depths of the tube. By removing the Resazurin indicator, the medium avoids any potential toxicity the dye might have on extremely sensitive strains and prevents color interference during the testing of pigmented pharmaceutical or clinical products.
Advantages
- Interference-Free: Eliminates potential inhibitory effects or color masking caused by redox dyes like Resazurin.
- Optimized for Pigmented Samples: Ideal for testing products with natural colors or high turbidity where a color-changing indicator would be difficult to read.
- Versatile Growth Support: Capable of recovering a wide variety of microorganisms, including obligate anaerobes, without specialized equipment.
- Stable Anaerobiosis: The combination of reducing agents and low-level agar ensures a reliable anaerobic environment in the lower portions of the medium.
- Recovery of Stressed Cells: Highly nutritious formulation facilitates the growth of sublethally injured organisms in sterility testing protocols.
Instructions for use
Suspend 29.75 g of the powder in 1 liter of distilled or deionized water. Mix thoroughly and heat with frequent agitation; boil for one minute to ensure complete dissolution. Preparation: Distribute into tubes or flasks and sterilize by autoclaving at 121 °C for 15 minutes. Note: If the medium is stored for an extended period, it is recommended to reheat it in a boiling water bath once to expel dissolved oxygen before use. Cool rapidly to room temperature before inoculation. Incubate at 30–35 °C for 7 to 14 days and examine for turbidity as an indicator of growth.
Technical specifications
| Catalogue number | 1516 |
| Brand | Condalab |
| Application | Sterility testing and cultivation of anaerobes in pigmented samples |
| Typical Composition (g/L) | Pancreatic Digest of Casein (15.0); Yeast Extract (5.0); Glucose (5.5); Sodium Chloride (2.5); L-Cystine (0.5); Sodium Thioglycollate (0.5); Bacteriological Agar (0.75) |
| Final pH (at 25 °C) | 7.1 ± 0.2 |
| Preparation | 29.75 g/L |
| Storage Temperature | 2 – 25 °C |
Available packaging options
| 1516 | 500 g plastic bottle |
| Brand | Condalab |
| Pack size | 500 g |
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