Brand:
Thermo ScientificTM OxoidTM
- Oxoid Raka-Ray Agar Base is a medium for the isolation of lactic acid bacteria in beer and brewing processes.
- Requires supplementation with phenylethanol, sorbitan mono-oleate, and cycloheximide Part No. SR0222C.
Raka-Ray Agar Base, Oxoid Composition
| Typical Formula* |
gm/litre
|
| Yeast extract |
5.0
|
| Tryptone |
20.0
|
| Liver concentrate |
1.0
|
| Maltose |
10.0
|
| Fructose |
5.0
|
| Glucose |
5.0
|
| Betaine HCL |
2.0
|
| Diammonium hydrogen-citrate |
2.0
|
| L-Aspartic acidâ |
2.5
|
| L-Glutamic acidâ â |
2.5
|
| Magnesium sulphate. 7H2O |
2.0
|
| Manganese (II) sulphate. 4H2O |
0.66
|
| Potassium phosphate |
2.0
|
| N-Acetyl glucosamine |
0.5
|
| Agar |
17.0
|
| pH 5.4 ± 0.2 @ 25°C |
|
Raka-Ray Agar, Oxoid Preparation:
Suspend 77.1g in 1 litre of distilled water. Add 10ml of sorbitan mono-oleate and 7ml of 0.1% Cycloheximide Solution (SR0222). Sterilise by autoclaving at 121°C for 15 minutes. Cool to 50-55°C and aseptically add 3g of phenylethanol. Pour into sterile Petri dishes or distribute into 4ml volumes held at 55°C if the overlay technique is to be used.
Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.
Precautions
Although the concentration of cycloheximide in the medium is below toxic levels, precautions should be observed as detailed under HAZARDS section.