Appearance (Colour)
Cream to yellow
Appearance (Form)
Free flowing, homogeneous powder
Solubility
69.05 gm/liter
Solubility before autoclaving (Clarity)
Clear to slightly opalescent
Gel strength
Firm, comparable with 1.5% agar gel
pH (25°C)
7.2 ± 0.2
Prepared Medium Appearance after autoclaving (Clarity)
Slightly opalescent gel
Prepared Medium Appearance after autoclaving (Colour)
Yellow
Cultural Response
Inoculate and incubate at 30-37°C for 24-48 hours
Organism
Listeria monocytogenes ATCC 19118
Inoculum (cfu) 10-100
Growth : Good
Recovery Rate : >= 50.0%
Colony colour : Blue/green plus halo
Organism
Listeria innocua ATCC 33090
Inoculum (cfu) 10-100
Growth : Good
Recovery Rate : >=50.0%
Colony colour : Blue/green no halo
Organism
Escherichia coli ATCC 25922
Inoculum
Growth : Inhibited
Applications
A selective and differential chromogenic medium recommended for rapid and direct identification of listeria species.
Principle
Enzymatic digest of animal tissue, enzymatic digest of casein and Yeast extract provides the nitrogenous sources of nutrients. Lithium chloride inhibits the non-targeted organisms. The combination of phospholipase enzyme reaction and chromogenic substrate aids in easy differentiation of Listeria monocytogenes (blue colonies surrounded by opaque halo), from other Listeria species.
Composition
Ingredients
gm/lt.
Enzymatic digest of animal tissue
18.00
Enzymatic digest of casein
6.00
Sodium pyruvate
2.00
Glucose
2.00
Magnesium glycerophosphate
1.00
Magnesium sulphate anhydrous
0.50
Sodium chloride
5.00
Yeast extract
10.00
Lithium Chloride
10.00
Disodium hydrogen phosphate anhydrous
2.50
Chromogenic mixture
0.50
Agar
12.00
Directions
1. Add 34.50 gm powder to 480ml distilled/purified water and mix thoroughly.
2. Gently heat and bring to boiling.
3. Autoclave at 15 psi pressure at 121°C for 15 minutes. If desired, aseptically add 1 vial of listeria selective supplement, mix well.
