Listeria sp./Listeria monocytogenes Chromogenic Detection System

R&F® Listeria sp./Listeria monocytogenes Chromogenic Detection Kit

A Selective & Differential Medium For Detecting Nonpathogenic & Pathogenic Listeria On A Single Plate. Presumptively positive colonies of nonpathogenic Listeria sp. appear pink, whereas Listeria monocytogenes and Listeria ivanovii appear as blue-green to blue-violet colonies with or without a precipitate after 42-48 hours at 35°C.

Kit includes 250g Bottle of Powder & Two Full Supplement Boxes – Makes 220-240 Plates

Key Advantages:

• This highly differential system is based on specific chro- mogenic substrates in the plating medium that simulta- neously differentiate both nonpathogenic Listeria species (L. innocua, L. seeligeri. L. welshimeri, and L. grayi) as pink colonies and the pathogenic Listeria species (L. monocytogenes and L. ivanovii) as blue-green to blue-violet colonies on a single plate in 42-48 h at 35°C. 

• Unlike selective/differential agar for Listeria species that depend on the detection of only ß-glucosidase activity and produce a single color for colonies for all Listeria species, the differentiation mechanism in this system works by the combination of indoxyl derivative chromogenic sub- strates that produce positive color reactions for colonies of nonpathogenic Listeria sp. that are pink due to their ß- glucosidase activity, and blue-green to blue-violet for the pathogenic species depending on the strain-specific balance of ß-glucosidase (pink) and phosphatidylinositol-specific- phospholipase C (blue) activities. 

• The agar surface of the plates have an opaque white back- ground that facilitates differentiation of colored colonies of both groups of Listeria organisms growing on the surface of the plate. 

• A rapid and convenient fluorogenic test and acid from rhamnose are provided in the system that differentiates Listeria monocytogenes from Listeria ivanovii within 6 hours.

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