Beef Extract Agar

Intended Use

Beef Extract Agar (DM1473) is recommended for routine cultivation of non-fastidious bacteria.

Product Summary and Explanation

Majority of organisms to be studied in medical bacteriology are either pathogens or commensals of the human body, and
to facilitate suitable growth an artificial culture medium should provide nutrients and a pH (about 7.2) approximating to
those of the tissues and body fluids. Many of these nutrients are supplied by aqueous extracts of beef and peptone,
which is a product of the digestion of protein for routine purposes.
(1) Beef Extract is recommended for use where
uniform composition of media is important.
Beef Extract Agar can be used as a general-purpose nutrient medium and is also recommended for preparation of pure
culture of Candida species for carrying out fermentation studies.(2)

Principles of the Procedure

Beef Extract Agar is a non-selective nutrient medium and contains beef extract and peptic digest of animal tissue as a
source of nitrogen and carbon. Sodium chloride is a source of electrolytes and helps to maintain the osmotic balance of
the medium.

Formula / Liter

Ingredients	Gms / Liter
Peptic digest of animal tissue	: 10.00
Beef extract	: 3.00
Sodium chloride	: 5.00
Agar	: 15.00
Final pH: 7.6 ± 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 33 grams of the medium in one liter of distilled water.
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 into sterile Petri plates.

Quality Control Specifications

Dehydrated Appearance	: Cream to yellow homogeneous free flowing powder
Prepared Medium	: Yellow coloured, clear to slightly opalescent gel forms in Petri plates
Reaction of 14.9% Solution	: pH: 7.2 ± 0.2 at 25oC
Gel Strength	: Firm, comparable with 1.5% Agar gel

Expected Cultural Response: Cultural characteristics observed after an incubation at 35-37°C for 18-48 hours.

Sr. No.	Organisms	Results to be achieved
Sr. No.	Organisms	Inoculum (CFU)	Growth	Recovery
1.	Candida albicans ATCC 10231	50-100	good-luxuriant	>=70%
2.	Escherichia coli ATCC 25922	50-100	good-luxuriant	>=70%
3.	Pseudomonas aeruginosa ATCC 27853	50-100	good-luxuriant	>=70%
4.	Salmonella Typhi ATCC 6539	50-100	good-luxuriant	>=70%
5.	Staphylococcus aureus ATCC 25923	50-100	good-luxuriant	>=70%

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.