HiCrome™ ECC Selective Agar (ECC Selective Agar, HiCrome™)

[所属分类:培养基配方] [发布时间:2021-4-7] [发布人: ] [阅读次数:] [返回]

HiCrome™ ECC Selective Agar

(ECC Selective Agar, HiCrome™)

培养基配方

Composition per liter:
Agar ............................................................................................10.0g
Peptone, special ............................................................................6.0g
Casein enzymic hydrolysate .........................................................3.3g
NaCl..............................................................................................2.0g
Sodium pyruvate...........................................................................1.0g
Tryptophan....................................................................................1.0g
Sorbitol..........................................................................................1.0g
Na 2 HPO 4 .......................................................................................1.0g
NaH 2 PO 4 .......................................................................................0.6g
Tergitol 7 ® ...................................................................................0.15g
Chromogenic mixture.................................................................0.43g
pH 6.8 ± 0.2 at 25°C
Source: This medium is available as a premixed powder from HiMedia.
Preparation of Medium:  Add components to distilled/deionized water and bring volume to 1.0L. Mix thoroughly and heat with frequent agitation until components are completely dissolved (approximately 35 min). Do not autoclave. Cool to 45°–50°C. Pour into sterile Petri dishes. Medium may show haziness.
Use: For detection of Escherichia coli and coliforms in water and food samples.Tergitol inhibits Gram-positive as well as some Gram-nega-tive bacteria other than coliforms. The chromogenic mixture contains two chromogenic substrates as Salmon-GAL and X-glucuronide. The enzyme b- 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. E. 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.