Thermo Scientific™ Oxoid™ Listeria Selective Oxford Agar Base (Dehydrated)

Foodborne infection by Listeria monocytogenes has prompted increased concern for detecting this organism in foods, in the environment and in pathological specimens from both human and animal subjects. The ability to isolate the organism has been impeded in the past by lack of an effective selective medium, as Listeria monocytogenes can be easily and completely overgrown by competing flora.

Use Listeria Selective Oxford Agar Base for selective isolation and detection of Listeria monocytogenes from food and environmental samples.

• Easy-to-read: Listeria monocytogenes form brown colored colonies with black zones due to aesculin hydrolysis.
• An FDA/BAM specified plating medium for Listeria monocytogenes isolation³.

The Listeria Selective Oxford Agar Base utilizes the selective inhibitory components and the indicator system―aesculin and ferrous iron for the isolation or differentiation of Listeria monocytogenes. Listeria monocytogenes hydrolyzes the aesculin, producing black zones around the colonies due to the formation of black iron phenolic compounds derived from the aglucon. Gram-negative bacteria are completely inhibited. Most unwanted Gram-positive species are suppressed, but some strains of enterococci grow poorly and exhibit a weak aesculin reaction, usually after 40 hours incubation. Some staphylococci may grow as aesculin-negative colonies.

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Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.