KM0121 – Listeria Isolation Medium (Oxford)

//KM0121 – Listeria Isolation Medium (Oxford)

KM0121 – Listeria Isolation Medium (Oxford)

Listeria isolation medium (Oxford) is based on the formulation described by Curtis et al. and is used for the isolation and identification of Listeria spp. in food and clinical laboratories.
Columbia agar base provides the required carbon, nitrogen and vitamins in the medium. Lithium chloride is included to inhibit enterococci. Aesculin is present as an indicator; Listeria spp. will hydrolyse aesculin and the associated reaction with the ferric ammonium citrate gives rise to a black precipitate around the colonies.
Selectivity is enhanced by addition of Listeria Oxford selective supplement (LS0030). This contains acriflavine, cefoxitin, colistin, fosfomycin and amphotericin to inhibit any yeasts present and some other Gram-positive and Gram-negative organisms that may be present in specimens.

Related Supplements :
LS0030 Listeria Oxford Selective Supplement

SKU: KM0121 Category:

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
Listeria monocytogenes NCTC 11994 Growth, grey colonies with dark diffusion around colonies
Listeria innocua NCTC 11288 Growth, grey colonies with dark diffusion around colonies
Enterococcus faecalis NCTC 12697 Inhibited
Escherichia coli NCTC 12241 Inhibited

 

Formula*

g/L
Columbia agar base 41.0
Aesculin 1.0
Ferric ammonium citrate 0.5
Lithium chloride 15.0
Total 57.5
*Adjusted/supplemented as required to meet performance requirements

Preparation

Suspend 57.5g 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 aseptically add 2 vials of selective supplement LS0030. Mix well and dispense into appropriate sterile containers.