MacConkey Agar with Salt

MacConkey Agar with Salt

KM0124 MacConkey Agar with Salt is a selective medium for the isolation and differentiation of bile tolerant Gram-negative (enteric) and Gram-positive (staphylococci and enterococci) organisms in all areas of bacteriology.

MacConkey Agar with Salt is based on the formulation by MacConkey in 1900. Staphylococcus and Enterococcus spp. are able to grow due to the omission of crystal violet from this formulation. This medium is recommended by the World Health Organisation and the Department of Health for the bacteriological examination of water, and KM0124 is recommended as a differential primary isolation media by the UK Standards for Microbiology Investigations.

Additional Information

Shelf Life (days)

Storage Temp (°C)

Dehydrated Medium Appearance

Prepared Medium Appearance

Dehydrated Medium Colour

Prepared Medium Colour

Dehydrated pH

Prepared pH

Product Description

Organisms Ref. No Result
Escherichia coli NCTC 12241 Growth: Pink/red colonies
Proteus mirabilis NCTC 10975 Growth: Yellow colonies
Salmonella typhimurium NCTC 12023 Growth: Pale straw colonies
Enterococcus faecalis NCTC 12697 Growth: Pink colonies
Staphylococcus aureus NCTC 12981 Growth: Pink colonies
Shigella sonnei NCTC 8574 Growth: Colourless colonies
Klebsiella aerogenes NCTC 10006 Growth: Red/orange colonies
Pseudomonas aeruginosa NCTC 12903 Growth: Straw colonies

Formula*

g/L
Peptone 20.0
Lactose 10.0
Bile salts 5.0
Sodium chloride 5.0
Neutral red 0.05
Agar 12.0
Total 52.0
*Adjusted/supplemented as required to meet performance requirements

Preparation

Suspend 52 g of the medium in one litre of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes. Sterilise at 121°C for 15 minutes with frequent stirring to completely dissolve the medium. Cool to 45-50°C and dispense into appropriate sterile containers.