ELEX Biological Products (Shanghai) Co., Ltd.
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Microbiology Test
Microbiology Test

Liquid Chromogenic Culture Media

Liquid Chromogenic Culture Medium

Coliforms and E. coli liquid chromogenic medium


Performance Characteristics of Liquid Chromogenic Culture Media

1. It is included in the "Japan Food Hygiene Guide" (2004 edition) with strong authoritative influence.

2. There are two kinds of chromogenic substances, which can directly recognize coliforms and E. coli.

3. The test results can be obtained within 24 hours, but BGLB needs 48 hours.

4. No need for a fermentation tube and a constant temperature pool with low cost and easy operation.

5. No need to prepare medium and wash tubes (except XM powder medium).

6. No need for identification and supplementation experiments such as EMB culture.

7. E.coli O157 cannot be identified separately but qualitative testing only.


Product Details of Liquid Chromogenic Culture Media

NameModelApplicationCapacityPackingValidity Period
Liquid chromogenic culture mediumXM-30For 1ml sample inspection10ml/cup128 cups/carton1 year
Liquid chromogenic culture mediumXM-31For 10ml sample inspection10ml/cup128 cups/carton
Liquid chromogenic culture mediumXM-32For 5ml sample inspection5ml/cup128 cups/carton
XM powder mediumXM0001For preparing medium8.5g/bag20 bags/carton3 years
MT openerOS-01For MT container opening/1pc/



Usage Method of Liquid Chromogenic Culture Media

1. Container surface sterilization: The surface of the aluminum foil should be disinfected with an alcohol lamp before use.

2. Opening: Open the aluminum foil with an MT opener (OS-01) or open directly with a sterile pipette.

3. Inject the sample diluent: use a pipette to inject the sample dilution into the cup

XM-30: 1ml, XM-31: 10ml, XM-32: 5ml

4. Cultivation: Culture time: 24 hours; Culture temperature: 36 ± 1 °C

5. Disposal: Dispose of them after sterilization

※XM powder medium usage: Dissolve 500ml of pure water per bag, inject 10ml into the test tube, autoclave, then inject 1ml sample, and incubate at 36±1°C for 24 hours. The identification method is the same.


Coloring Principle

Coliforms positive

There is a special β-galactosidase only exit in the coliforms. It can be used as an indicator enzyme for coliform bacteria, which catalyzes the hydrolysis of the substrate X-GAL to form 5,5-dibromo -4,4-dichloro indigo, appearing light blue ~ purple-blue.

E. coli positive

β--glucuronidase can be used as an indicator enzyme for Escherichia coli; because β-glucuronidase can be observed in Escherichia coli, Salmonella and Shigella in intestinal bacteria, and 95% of E. coli contains β-glucuronidase. It catalyzes the hydrolysis of MUG to form 4-methylumbelliferon, which exhibits fluorescence at 366 nm ultraviolet light and is visually discernible under indoor light intensity.


Operation and Coloring of Liquid Chromogenic Culture Media


ELEX Liquid Chromogenic Culture Media step1

Step 1


ELEX Liquid Chromogenic Culture Media step2

Step 2



ELEX Liquid Chromogenic Culture Media Primary color negative

Primary color - negative


ELEX Liquid Chromogenic Culture Media Blue coliforms positive

Blue - coliforms positive


ELEX Liquid Chromogenic Culture Media Fluorescence E

Fluorescence--E. coli positive

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