• Chromogenic Listeria Agar Meets Iso Recommendations

Laboratory products

Chromogenic Listeria Agar Meets Iso Recommendations

The recently launched Oxoid Chromogenic Listeria Agar (OCLA), for the isolation, enumeration and presumptive identification of Listeria spp. and Listeria monocytogenes from food, conforms to the formulation described by Ottaviani and Agosti in ISO 11290 parts 1 & 2:1997.

The selective chromogenic medium, comprised of OCLA Base (ISO) [CM1084] and Listeria Selective Supplement (ISO) [SR0226E], detects the ?-glucosidase activity common to all Listeria species resulting in distinct blue colonies. The addition of phosphatidylinositol at 2g/L, as recommended in the ISO formulation, detects phosphatidylinositol phospholipase C (PIPLC) produced by pathogenic Listeria species. Alternatively, the addition of Oxoid Chromogenic Listeria Differential Supplement [SR0228E] detects phosphatidycholine phospholipase C (PCPLC). Either supplementation results in a clearly visible, opaque white halo around pathogenic Listeria colonies.

Both PIPLC and PCPLC are associated with the virulence of Listeria, but detection of either enzyme is sufficient for the identification of pathogenicity. Listeria monocytogenes is the most common pathogenic Listeria species, but some strains of L. ivanovii may also possess these enzymes. Pathogenic L. ivanovii will also produce blue colony halos on OCLA (ISO).

Digital Edition

ILM Guide 2025/26

June 2025

Buyers' Guide Listings- Product Listings by Category- Suppliers Listings (A-Z)Chromatography Articles- Setting the power coefficient and the baseline to linearise the signal of the evaporative ligh...

View all digital editions

Events

AUTOMATICON

Jun 24 2025 Warsaw, Poland

CPhI & P-MEC China 2025

Jun 24 2025 Shanghai, China

Discovery & Development Europe 2025

Jul 01 2025 Basel, Switzerland

MMC 2025

Jul 01 2025 Manchester, UK

analytica Lab Africa

Jul 08 2025 Johannesburg, South Africa

View all events