Casein Hydrolysate Agar w/ 1.5% Agar

Intended Use

Casein Hydrolysate Agar w/ 1.5% Agar (DM1313) is recommended for a general purpose culture medium.

Product Summary and Explanation

Casein Hydroysate Agar w/1.5% Agar is the modification of medium recommended by APHA(1) and is used as a general purpose culture medium.

Principles of the Procedure

Casein Hydroysate Agar w/1.5% Agar contains casein hydrolysate, beef infusion, and peptic digest of meat which provide the carbonaceous and nitrogenous compounds to support the growth of microbes in the medium. Yeast autolysate provides essential vitamins and necessary growth factors required for metabolism of wide number of bacteria. Sodium phosphate helps buffering of media whereas sodium chloride balances the osmotic equilibrium. Glycerol is used as source of carbohydrate and energy required for the growth of the microorganisms in the medium. Agar is added as a solidifying agent of the medium.

Formula / Liter

Ingredients	Gms / Liter
Casein enzymic hydrolysate	: 5.00
Beef infusion from	: 150.00
Peptic digest of animal tissue	: 5.00
Yeast autolysate	: 1.50
Sodium phosphate	: 2.50
Sodium chloride	: 5.00
Agar	: 15.00
Final pH: 7.8 ± 0.2 at 25°C
Formula may be adjusted and/or supplemented as required to meet performance specifications

Precautions

1. For Laboratory Use only.
2. IRRITANT. Irritating to eyes, respiratory system, and skin.

Directions

1. Suspend 35.5 grams of the medium in one liter of distilled water containing 22 ml glycerol.
2. Heat to boiling, to dissolve the medium completely.
3. Autoclave at 121°C, 15 psi pressure, for 15 minutes / validated cycle.
4. Mix well and pour in sterile Petri plates.

Quality Control Specifications

Dehydrated Appearance	: Yellow coloured homogeneous free flowing powder
Prepared Medium	: Light to medium amber coloured, clear to slightly opalescent gel forms in Petri plates
Reaction of 3.55% Solution	: pH: 7.8 ± 0.2 at 25°C
Gel Strength	: Firm, comparable with 1.5% Agar gel

Expected Cultural Response: Cultural characteristics observed after an incubation at 35-37°C for 18-24 hours.

Sr. No.	Organisms	Results to be achieved
		Growth
1.	Enterococcus faecalis ATCC 29212	good- luxuriant
2.	Staphylococcus aureus ATCC 25923	good- luxuriant

The organisms listed are the minimum that should be used for quality control testing.

Test Procedure

Refer appropriate references for specific test procedures.

Results

Refer appropriate references and test procedures for interpretation of results.

Storage

Store the sealed bottle containing the dehydrated medium at 10 – 30°C. Once opened and recapped, place container in a low humidity environment at the same storage temperature. Protect from moisture and light.

Expiration

Refer to the expiration date stamped on the container. The dehydrated medium should be discarded if not free flowing, or if the appearance has changed from the original color. Expiry applies to medium in its intact container when stored as directed.

Limitations of the Procedure

1. For identification, organisms must be in pure culture. Morphological, biochemical and/or serological tests should be performed for final identification.
2. Consult appropriate texts for detailed information and recommended procedures.