Product No.	Product Category	Specification
HCM005	Dehydrated Culture Medium	500g/bottle

Intended Use

For the selective enrichment, enumeration and confirmation of coliform bacteria from food and animal feed and other materials.

Principle and Interpretation

The lactose content of this medium favors the growth of lactose-positive bacteria, especially of coliform bacteria and E. coli. The bile salts, however, largely inhibit the growth of Gram-positive bacteria or microorganisms which are not adapted to the intestinal environment. Lactose-positive bacteria metabolize lactose with gas formation.

Formulation

Ingredients	/liter
Tryptose or trypticase ( Enzymatic digest of casein)	20.0g
Lactose	5.0g
Bile Salts No. 3	1.5g
K2HPO4	4.0g
KH2PO4	1.5g
NaCl	5.0g
pH6.9±0.2 at 25°C

Preparation

Dissolve 37 g in 1 L of purified water. Dispense into tubes containing Durham tubes. Autoclave 15 min at 121 °C. The Durham tubes shall not contain any air bubbles after autoclaving.

Quality Control

Cultural characteristics observed after incubation at 43-45°C for 24 hours

Quality control strains	Approx. Inoculum(CFU)	Expected Results
		Growth	Gas
Escherichia coli  ATCC25922	10-100	Turbid growth	Positive
Staphylococcus aureus  ATCC6538	> 104	Partial to complete inhibition	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

ISO7251-2005 microbiology of food and animal feeding stuffs —– Horizontal method for the detection and enumeration of presumptive Escherichia coli —- Most probable number technique.

BAM Media M49: EC Broth