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HiCrome Coliform Agar (Coliform Agar, HiCrome)

[所属分类:培养基配方] [发布时间:2021-11-22] [发布人:网站管理员2] [阅读次数:] [返回]

HiCrome Coliform Agar

(Coliform Agar, HiCrome)

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

Composition per liter:

Agar ..................................................................12.0g

Sodium chloride..................................................5.0g

Peptone, special ..................................................3.0g

K2HPO4...............................................................3.0g

KH2PO4...............................................................1.7g

Sodium pyruvate.................................................1.0g

Tryptophan..........................................................1.0g

Chromogenic mixture .........................................0.2g

Sodium lauryl sulfate..........................................0.1g

pH 6.8 ± 0.2 at 25°C

Source: This medium is available from Fluka, Sig

ma-Aldrich.

Preparation of Medium: Add components to

distilled/deionized water and bring volume to 1.0L.

Mix thoroughly. Gently heat while stirring and bring

to boiling. Autoclave for 15 min at 15 psi pressure–

121°C. Pour into sterile Petri dishes.

Use: For the simultaneous detection of Escherichia

coli and total coliforms in water and food samples.

Sodium lauryl sulfate inhibits gram-positive organ

isms. The chromogenic mixture contains two chro

mogenic substrates as Salmon-GAL and X-glucu

ronide. The enzyme β-D-galactosidase produced by

coliforms cleaves Salmon-GAL, resulting in the

salmon to red coloration of coliform colonies. The

enzyme β-D-glucuronidase produced by E. coli

cleaves X-glucuronide. Escherichia coli forms dark

blue to violet colored colonies due to cleavage of

both Salmon-GAL and X-glucuronide. The addition

of tryptophan improves the indole reaction, thereby

increasing detection reliability in combination with

the two chromogens.