Chromagar™ Listeria Agar

Isolation of Listeria monocytogenes in food products for human consumption and environmental samples.

2 AFNOR validations
CHROMagarTM Listeria
First validation for isolation and confirmation of Listeria monocytogenes.
(Validation certificate No: CHR 21/1-12/01).
Second validation for enumeration of Listeria monocytogenes.
(Validation certificate No: CHR 21/2-12/06).

METHOD FOR ISOLATION AND CONFIRMATION
AFNOR-validated
(x) g or (x) ml of sample in 9 (x) ml of half Fraser broth
24±2 h at 30°C.

Isolation on CHROMagarª Listeria with 100 µl
24±2 h at 37°C.

Characteristic colonies:
blue, surrounded by a white halo

YES NO

Confirmation with Absence of Listeria monocytogenes
CHROMagarª Identification Listeria
20 h ± 2 h at 37°C.
YES NO

Presence of Listeria monocytogenes

PRINCIPLE
The CHROMagarTM Listeria medium is used for the isolation or enumeration of Listeria monocytogenes from food products for human consumption and environmental samples.
- Listeria monocytogenes colonies are detected thanks to their blue colour and surrounding white halo.
- This halo is linked to a phospholipase activity involved in the infectious process of pathogenic Listeria strains.
The CHROMagarTM Listeria Identification medium allows the confirmation of Listeria monocytogenes strains in mauve with a white halo from colonies isolated directly from CHROMagarTM Listeria.

METHOD FOR ISOLATION AND CONFIRMATION
AFNOR-validated rapid method for CHROMagarª Listeria:
(Validation certificate No: CHR 21/1-12/01).
- After 24 h pre-enrichment in half Fraser (i.e. without supplement). See below.

Blue Colony
surrounded by a halo
=
Listeria monocytogenes

CHROMOGENIC MEDIUM
for detection, confirmation
and enumeration
of Listeria monocytogenes
DEVELOPED
by A. RAMBACH