MacConkey Agar without Salt & Crystal Violet

//MacConkey Agar without Salt & Crystal Violet

MacConkey Agar without Salt & Crystal Violet

SKU: KM0011 Category:

This medium was first introduced by MacConkey in 1905 for the isolation and differentiation of lactose and non-lactose fermenting enteric bacteria containing swarming strains of Proteus spp. MacConkey agar without salt and crystal violet is a differential medium that restricts swarming of Proteus spp. as sodium chloride is omitted from the medium to provide an electrolyte deficient medium. The omission of crystal violet permits the growth of Staphylococcus spp. and Enterococcus spp. The peptone is the nitrogen, carbon and vitamin source in this medium. Lactose is the fermentable carbohydrate. Lactose fermentation causes a local pH drop around the colonies which will react with the pH indicator, neutral red, and hence aids in differentiation. Bile salts act as the selective agent.

Related Supplements :
LS0189 Cefotaxime Supplement (1mg/L)

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
Staphylococcus aureus NCTC 12981 Growth, pink colonies
Proteus mirabilis NCTC 10975 Growth, yellow colonies
Escherichia coli NCTC 12241 Growth, pink / red Colonies
Enterococcus faecalis NCTC 12697 Growth, pink colonies
Salmonella typhimurium NCTC 12023 Growth, straw colonies



Peptone 20.0
Lactose 10.0
Bile salts 5.0
Neutral red 0.075
Agar 13.0
Total 48.0
*Adjusted/supplemented as required to meet performance requirements


Suspend 48g of the medium in one litre of deionised / purified
water. Allow the medium to soak whilst mixing for 10 minutes. Heat with frequent agitation and boil for one minute to completely dissolve the medium. Sterilise at 121°C for 15 minutes. Cool to 45-50°C and aseptically dispense into appropriate sterile containers.