Dehydrated culture media
Giolitti-Cantoni Broth
For the selective enrichment of Staphylococcus aureus in food samples.
- Cat. No.
- LC-1232
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
- Also available
- Dehydrated medium, 1 format (LC-1287)
- Also available
- Ready-to-use medium, 1 format (LC-4228)
Giolitti-Cantoni Broth with potassium tellurite added is prepared according to the formula of Giolitti and Cantoni, for the enumeration, using the MPN method, and for the selective enrichment of coagulase positive staphylococci in foodstuffs and dried baby milk. It was designed by Giolitti and Cantoni to facilitate the growth of Staphylococcus aureus by incorporating sodium pyruvate in the formula, even when present in low numbers in food samples.
Key features
Applications
Selective isolation of Staphylococcus.
Industry
Dairy products, food.
Preparation
54.2 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes, then add potassium tellurite.
Principles and uses
The International Dairy Federation recommends this medium in a procedure for detecting S. aureus in dairy products, using it as an enrichment medium.
Tryptone and beef extract provide nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group, essential for bacterial growth. Mannitol is the fermentable carbohydrate providing carbon and energy. The growth of Gram-negative bacteria is inhibited by lithium chloride, whilst the Gram-positive bacilli are inhibited by glycine and the potassium tellurite. The high level of potassium tellurite is necessary to suppress the high numbers of contaminating organisms that could be expected.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Toasted |
| Color of the prepared medium | Amber |
| Final pH (25 °C) | 6.9 ± 0.2 |
| Amount per litre | 54.2 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Beef extract | 5 |
| D-mannitol | 20 |
| Glycine | 1.2 |
| Sodium chloride | 5 |
| Sodium pyruvate | 3 |
| Tryptone | 10 |
| Yeast extract | 5 |
| Lithium chloride | 5 |
Preparation and use
Preparation
Suspend 54.2 grams of medium in one liter of distilled water. Mix well and dissolve by heating with frequent agitation. Boil for one minute until complete dissolution. Dispense 19 mL amounts into test tubes and sterilize in autoclave at 121 °C for 15 minutes. Cool to 45-50 °C and aseptically add 0.3 mL of 3.5% potassium tellurite (LC-5208) or 1 mL of 1% potassium tellurite to each tube.
Instructions for use
Duplicate tubes should be inoculated with 1 mL of each serial dilution and the caps tightened. Incubate at 35 ± 2 °C for 40-48 hours, examining the tubes daily.
The test is considered negative for S. aureus if no blackening of the medium is observed. If blackening is present throughout or at the bottom of the tube, subculture to an isolation medium, such as Baird Parker Agar Base (LC-1100), and observe for positive growth of black colonies surrounded by a clearing zone.
Quality control
Microbiological test
Incubation conditions: 35 ± 2 °C / 40-48 h.
| Microorganism | Specification |
|---|---|
| Escherichia coliATCC 25922 | Inhibited growth |
| Staphylococcus aureusATCC 25923 | Good growth (black) |
| Staphylococcus aureusATCC 6538 | Good growth (black) |
| Micrococcus luteusATCC 9341 | Inhibited growth |
Bibliography
- Giolitti, C. and Cantoni, C. (1966) "A Medium for the Isolation of Staphylococci from Foodstuffs", J. Appl. Bact. 29, 395.
- International Dairy Federation. 1978 IDF Standard GOA: 1978.
What you receive
The product
Shipped under controlled temperature when the product requires it.
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