Dehydrated culture media
KAA Presumptive Broth
For the presumptive detection of intestinal enterococci in foods according to Mossel.
- Cat. No.
- LC-1209
- Category
- Dehydrated culture media
- Format
- 500 g
- Storage
- 2 to 25 °C
- Minimum guaranteed shelf life
- 15 months
KAA Presumptive Broth (Kanamycin, Aesculin, Azide) is a selective medium for the isolation of intestinal enterococci in foods. KAA Presumptive Broth is used in conjunction with KAA Confirmatory Agar (LC-1027).
Key features
Applications
Detection of enterococci.
Industry
Food.
Preparation
33 g in one liter of distilled water; boil for one minute, sterilize in autoclave at 121 °C for 15 minutes.
Principles and uses
Kanamycin, sodium azide and sodium citrate have a great inhibitory effect on the accompanying bacterial flora, they inhibit the growth of Gram-positive and Gram-negative bacteria, and the medium is highly selective for esculin-hydrolyzing enterococci. Ferric ammonium citrate is an indicator which detects the esculin-hydrolysing bacteria. They hydrolyze the glucoside esculin to give glucose and esculetin. Tubes have a black color due to the reaction of the resulting esculetin with the iron ions. Tryptone provides 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. Sodium chloride supplies essential electrolytes for transport and osmotic balance.
The presence of intestinal enterococci is an indicator for faecal contamination, especially when the contamination occurred long ago and the less resistant coliform bacteria, including Escherichia coli, are already dead when the analysis is carried out.
Technical specifications
| Solubility | Without residues |
|---|---|
| Appearance | Fine powder |
| Color of the dehydrated medium | Beige |
| Color of the prepared medium | Tournasol |
| Final pH (25 °C) | 7.0 ± 0.2 |
| Amount per litre | 33 g |
| Storage | 2 to 25 °C |
Formula
| Ingredient | g/L |
|---|---|
| Esculin | 1 |
| Ferric ammonium citrate | 0.5 |
| Kanamycin sulfate | 0.02 |
| Sodium azide | 0.15 |
| Sodium chloride | 5 |
| Sodium citrate | 1 |
| Tryptone | 20 |
| Yeast extract | 5 |
Typical formula in g/L, adjusted and/or supplemented as required to meet performance criteria.
Preparation and use
Preparation
Suspend 33 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. Dispense into appropriate containers and sterilize in autoclave at 121 °C for 15 minutes.
Instructions for use
Inoculate 1 mL of sample in tubes with 9 mL of single-strength medium. Incubate at 35 ± 2 °C for 24-48 hours. Presumptive positive tubes have a brown-black color.
Quality control
Microbiological test
Incubation conditions: 35 ± 2 °C / 24-48 h.
| Microorganism | Specification | Characteristic reaction |
|---|---|---|
| Escherichia coliATCC 25922 | Total inhibition | |
| Enterococcus faecalisATCC 29212 | Good growth | Esculin hydrolysis (+) |
| Enterococcus faeciumATCC 6057 | Good growth | Esculin hydrolysis (+) |
| Staphylococcus aureusATCC 6538 | Moderate growth | Esculin hydrolysis (-) |
Bibliography
- M.R. Pascual Anderson. Técnicas para Examen Microbiológico de Alimentos y Bebidas (Centro Nacional de Alimentación y Nutrición CeNAN) Madrid, 1982.
- Brandl, E. Aspergerger H., Pfleger, F. U-IBEN CH: Zum Vorkomment von D-streptokokken in Käse. 1985.
What you receive
The product
Shipped under controlled temperature when the product requires it.
Lot certificate
Every lot comes with its certificate.
Tracked shipment
Follow your shipment live, from our warehouse to your lab.
Other products in the same category
Frequently asked questions
Can I ask for formats other than those listed?
Yes: custom formats and OEM packs are available on request. Tell us the quantities you need.
How do I see the prices?
Prices are shown after you sign in to the customer area, with your account discount already applied.
How long does delivery take?
We give you the availability with the quote, within 24 hours of your request.