Salmonella Chromogenic Medium (GenerationⅡ)

Salmonella Chromogenic Medium (GenerationⅡ) is used for the rapid detection of food, water, milk, ice cream and meat and other samples of Salmonella. The colonies of salmonella are purple, E. coli and coliform bacteria are blue, and the other bacteria are yellow or colorless.

Ingredients (g/L):

*Adjusted and/or supplemented as required to meet performance criteria.

Directions:

Suspend 65g of the medium in 1L of distilled water, heat about 2 minutes, add a piece of CT additive when cooling down to 45-50℃, mix thoroughly, pour into petri dishes.

Warning: Prepared medium must be kept dry, can place inverted culture in incubator at 36 ± 1 ℃ for 1-2 hours.

Procedures:

1. Prepared sample solution according to national standards, SN standard, FDA standards or other methods.

2. Transfer 1mL sample solution into 9mL RVS Broth or other enrichment broth, enrichment culture for 24±2 hours at 36 ± 1 ℃;

3. Take one ring enrichment broth with a 3mm inoculation loop, streak to inoculate on Salmonella chromogenic medium, make two plates

4. Enrichment culture for 24±2 hours at 36 ± 1 ℃, The colonies of salmonella are purple, E. Coli and coliform bacteria are blue; the other bacteria are yellow or colorless.

5. For undermined colonies, streak them on nutrient agar plates, culture at 36 ± 1 ℃ for 12-16h, select single colony to do a full set of Salmonella biochemical tests.

Quality Control:

1. Appearance:

The dehydrate powder medium is homogeneous, having good flowability, milky white, prepared medium is colorless solid.

2. Microbial sensitivity test:

Incubated at 36 ± 1 ℃ 18-24h:

Methods limitations:

The medium can identify most of Salmonella; Specificity is up 98%, very high accuracy sometimes it needs do complementary tests

Typical features:

The colonies of salmonella are purple, E. coli and coliform bacteria are blue, the other bacteria are yellow or colorless.

Storage:

The prepared plates can be kept for 2-5 days, avoid direct exposure to light. The powder medium should be placed in a dark, dry place, storage temperature 2-8 ℃, avoid direct exposure to light.

Failure:

Dry powder media which are over the shelf life, caking and color variation cannot be used.

Note:

This medium is only for laboratory use.

Reference:

1. FRAMPTON, E.W., RESTAINO, L. a. BLASZKO, L.: Evaluation of ß-glucuronidase substrate  in a 24 hour direct plating method for Escherichia coli.  J. Food Protection, 51; 402-404 (1988).