Dehydrated culture media
Linden Grain Medium
For the trace detection of beverage-spoiling microorganisms e.g. yeasts, bacteria and moulds in the validation process of aseptic filling facilities.
- Cat. No.
- LC-2068
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
Linden Grain Medium allows standardised detection of beverage-spoiling bacteria, yeast and mould for validating aseptic filling lines for beverages with a pH value of between 4.0 and 6.5, such as soft drinks, juices and even dairy products. In the production of beverages with a low acid content, the filling process and the filling line itself may be a source of contamination with beverage-spoiling microorganisms. Presence of these organisms of the contaminant flora in the environment is indicated by turbid growth in the broth.
Key features
Applications
Detection (general use).
Industry
Dairy products, food, juices.
Preparation
29.5 g in one liter of distilled water; boil for one minute, distribute into appropriate containers and sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Media fill is the performance of an aseptic manufacturing procedure using a sterile microbiological growth medium in place of the drug solution. The beverages are prepared directly in product preparation tanks, processed in a heat exchanger and filled into cans or bottles. To allow possible weak points to be recognised, the filling process on aseptic lines needs to be examined and validated during commissioning or if major changes are made, such as in maintenance or service. In addition, annual revalidation is recommended even for unchanged filling processes in order to discover any contamination sources early on.
Casein peptone provides amino acids, nitrogen and other essential growth nutrients. Glucose is the main source of carbohydrates and energy. Yeast extract is the source of vitamins, particularly of the B-group. Magnesium sulphate and ammonium sulphate provide sources of sulfates and metallic ions. Monopotassium sulphate has a high buffering capacity.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Amber |
| Final pH (25 °C) | 4.2 ± 0.2 |
| Amount per litre | 29.5 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Glucose | 20 |
| Ammonium sulfate | 2 |
| Casein peptone | 2 |
| Magnesium sulfate | 1 |
| Monopotassium phosphate | 1 |
| Yeast extract | 3.5 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 29.5 grams of the medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Distribute into appropriate containers and sterilize in autoclave at 121 °C for 15 minutes.
Instructions for use
- Inoculate the sample in Linden Grain Medium with a sterile inoculating loop.
- Shake the medium gently with the loop.
- Incubate at 25-30 °C for 5 days.
Quality control
Microbiological test
Incubation conditions: 25-30 °C / 5 days.
| Microorganism | Specification |
|---|---|
| Candida albicansATCC 10231 | Good growth (turbidity) |
| Aspergillus brasiliensisATCC 16404 | Good growth (turbidity) |
| Saccharomyces cerevisiaeATCC 9763 | Good growth (turbidity) |
Bibliography
- U.S. Department of Health and Human Services, Food & Drug Administration, Centre for Drug Evaluation and Research, April 2012.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
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Tracked shipment
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