NUTRIENT AGAR

Code: CM0003 (Powder)
Code: CM0004 (Tablets)

A general purpose medium which may be enriched with up to 10% blood or other biological fluid.

Typical Formula *	gm/litre
`Lab-Lemco’ powder	1.0
Yeast extract	2.0
Peptone	5.0
Sodium chloride	5.0
Agar	15.0
pH 7.4 ± 0.2 @ 25°C

* Adjusted as required to meet performance standards.

Directions
Powder: Suspend 28g in 1 litre of distilled water. Bring to the boil to dissolve completely. Sterilise by autoclaving at 121°C for 15 minutes.
Tablets: Add one tablet to 5ml of distilled water and soak for 5 minutes. Sterilise by autoclaving at 121°C for 15 minutes.

Description
Nutrient Agar is a basic culture medium used to subculture organisms for maintenance purposes or to check the purity of subcultures from isolation plates prior to biochemical or serological tests.

In semi-solid form, agar slopes or agar butts, the medium is used to maintain control organisms¹.

Nutrient Agar is suitable for teaching and demonstration purposes. It contains a concentration of 1.5% agar to permit the addition of up to 10% blood or other biological fluid, as required. The medium, without additions, may be used for the cultivation of organisms which are not exacting in their nutritional requirements.

For a medium which is richer in nutrients, see Blood Agar Base No.2 CM0271.

Storage conditions and Shelf life
Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-8°C.

Appearance
Dehydrated medium: Straw coloured, free-flowing powder
Prepared medium: Straw coloured gel

Quality control

Positive controls:	Expected results
Staphylococcus aureus ATCC® 25923 *	Good growth; straw/white colonies
Escherichia coli ATCC® 25922 *	Good growth; straw colonies
Negative control:
Uninoculated medium	No change