Product No.	Product Category	Specification
HCM128	Dehydrated Culture Medium	500g/bottle

Intended Use

For r the detection and enumeration of coliform bacteria, in particular E. coli.

Principle and Interpretation

Crystal violet and bile salts largely inhibit the growth of Gram-positive accompanying bacterial flora. Lactose- positive colonies show a colour change to red of the pH indicator. E. coli colonies show a fluorescence under UV light.

Formulation

Ingredients	/liter
Yeast extract	3.0g
Peptone	7.0g
Bile salts	1.5g
Sodium chloride	5.0g
Lactose	10.0g
Neutral red	0.03g
Crystal violet	0.002g
Agar	15.0g
4-methylumbelliferyl-β-D-glucuronide (MUG)	0.1g
pH7.4±0.2 at 25°C

Preparation

Suspend 41.6 g in 1 L of distilled or deionized water. Heat with frequent agitation and boil to completely dissolve the powder. Do not autoclave. Cool to 45-50°C and pour into sterile petri dishes.

Quality Control

Cultural characteristics observed after incubation at 35-37°C for 18 – 24 hours.

Quality control strains	Approx. Inoculum (CFU)	Expected Results
		Recovery	Fluorescence
Escherichia coli  ATCC25922	50-200	Good, PR≥0.7	Positive
Citrobacter freundii  ATCC43864	50-200	Good, PR≥0.7	Negative
Staphylococcus aureus ATCC29212	>104	Inhibited, G≤1-	Negative

Storage and Shelf Life

2-30℃，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

FDA BAM Media M175