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产地：oxoid
货号：CM0309B
规格：500G
名称：W．L．营养琼脂，Wl nutrient agar
Description
WL Nutrient Agar (Medium), based on that of Green and Gray1 is recommended for the determination of the microbiological flora in brewing and fermentation processes. The medium is suitable for the differentiation of `wild’ yeasts from brewing yeasts2.
Reliable counts for brewers’ yeast are obtained with the medium at pH 5.5. Adjustment to pH 6.5 facilitates the counting of bakers’ and distillers’ yeasts.
Cycloheximide (SR0222) may be added to the medium at a final concentration of 4 mg/litre, to suppress yeast growth, the medium becomes selective for the bacterial contaminants of yeast cultures.
When making microbial counts with this medium the time and temperature of incubation will vary according to the materials tested and the organisms sought. Temperatures of 25°C are used for brewing materials and 30°C for bakers’ yeasts.
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. |