Salmonella Shigella (SS) Agar Modified

//Salmonella Shigella (SS) Agar Modified

Salmonella Shigella (SS) Agar Modified

SKU: KM0033 Category:

This is a selective medium for the isolation of Salmonella spp. and Shigella spp. from clinical specimens and food samples.
SS agar is a modification of the original DCA medium described by Leifson. The formulation for SS agar was later modified to improve the growth of Shigella spp.
SS agar modified differs from SS agar in that it has an alternation to the bile salts mixture, peptone, pH value, and total g/litre.
The peptone provides the required carbon, nitrogen and vitamins. Lactose is a fermentable carbohydrate and neutral red is a pH indicator.
Sodium thiosulphate and ferric citrate are used to detect hydrogen sulphide production indicated by the black centred colonies of hydrogen sulphite positive organisms.
Bile salts, sodium citrate and brilliant green inhibit Gram-positive bacteria and a number of different coliform bacteria.

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
Salmonella enteritidis NCTC 12694 Growth, translucent colonies with black centre
Shigella sonnei NCTC 8574 Growth, pale pink/yellow colonies
Enterococcus faecalis NCTC 12697 Inhibited



Peptone 10.0
Lactose 10.0
Bile salts 5.5
Sodium citrate 10.0
Sodium thiosulphate 8.5
Ferric citrate 1.0
Brilliant green 0.00033
Neutral red 0.025
Agar 12.0
Total 57.0
*Adjusted/supplemented as required to meet performance requirements


Suspend 57g 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. DO NOT AUTOCLAVE this medium. Cool to 45-50°C and aseptically dispense into appropriate sterile containers.