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Membrane Lactose Glucuronide Agar (MLGA)

[所属分类:培养基配方] [发布时间:2021-12-1] [发布人:网站管理员2] [阅读次数:] [返回]

Membrane Lactose Glucuronide Agar

(MLGA)

山东拓普生物工程有限公司培养基配方 http://www.topbiol.com

Composition per liter:

Peptone..............................................................40.0g

Lactose..............................................................30.0g

Agar ..................................................................10.0g

Yeast extract........................................................6.0g

Sodium lauryl sulfate..........................................1.0g

Sodium pyruvate.................................................0.5g

5-Bromo-4-chloro-3-indoxyl-

β-D-glucuronic acid ......................................0.2g

Phenol Red..........................................................0.2g

pH 7.4 ± 0.2 at 25°C

Source: This medium is available from Oxoid.

Preparation of Medium: Add components to

distilled/deionized water and bring volume to 1.0L.

Mix thoroughly. Autoclave for 15 min at 15 psi pres

sure–121°C. Cool to 45°–50°C. Pour into sterile Petri

dishes.

Use: For the direct enumeration of E. coli and

coliforms in foods by the membrane filtration meth

od. The chromogenic substrate 5-Bromo-4-chloro-3-

indoxyl-β-D-glucuronic acid (BCIG), is cleaved by

the enzyme β-glucuronidase and produces a blue

chromophore that builds up within the bacterial cells.

In addition, the incorporation of phenol red detects

lactose fermentation and results in yellow colonies

when acid is produced. Since coliform colonies are

lactose positive, they will appear yellow on this me

dium and as E. coli colonies are both lactose and β-

glucuronidase positive, they will appear green.