Specification

500g/bottle 250g/bottle

Intended Use

For the enumeration of coliforms in food and dairy products.

Principle and Interpretation

Peptone and yeast extract powder provides carbon and nitrogen sources and trace elements; lactose are fermentable sugars; sodium chloride maintains osmotic equilibrium; the 3rd bile salts and crystal violet inhibiting ram-positive bacteria, especially against Gram positive bacteria and fecal streptococci; neutral red as pH indicator.

Formulation

Ingredients	/liter
Yeast extract	3.0 g
Peptone or gelysate	7.0 g
NaCl	5.0 g
Bile salts or bile salts No. 3	1.5 g
Lactose	10.0 g
Neutral red	0.03 g
Crystal violet	0.002 g
Agar	15.0 g
pH7.4±0.2 at 25°C

Preparation

Weigh 41.5g of dry powder of this product, add 1L of distilled water or deionized water, stir, heat and boil until completely dissolved, , Do not autoclave. cool to room temperature and set aside.

Quality Control

The following quality control strains were inoculated and cultured at 30-35°C for 24h. The results are as follows:

Quality control strains	Recovery	Characteristic reaction
Escherichia coli ATCC25922	PR≥0.7	Purple-red or red colonies with a precipitation ring
Citrobacter freundii ATCC43864		Red colonies with recipitate rings

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Salmonella enterica serovar Typhimurium ATCC14028	–	Colorless translucent colonies
Enterococcus faecalis ATCC29212	G≤3	–

Storage and Shelf Life

2-30°C，Keep container tightly closed, avoid direct sunlight. Use before expiry date on the label.

Precautions

1. When weighing the dehydrated medium, please wear masks to avoid causing respiratory system discomfort 2. Keep container tightly closed after using to prevent clumping.

Waste Disposal

Microbiological contamination was disposed by autoclaving at 121°C for 30 minutes.

Revision

On June 14, 2024

References

BAM Media M174: Violet Red Bile Agar (VRBA)