The RIDASCREEN® Listeria (Art. No.: R4202) is a sandwich enzyme immune assay for the qualitative detection of Listeria spp. from pre-enrichment cultures of food samples and swab samples from the production environment. The pre-enrichment has to be performed using appropriate selective methods for Listeria spp. (e.g. selective primary enrichment in ½ Fraser broth followed by a selective secondary enrichment in Fraser broth).
RIDASCREEN® Listeria is a robust, reliable test used to detect Listera spp. which are relevant for food contaminations. To revive any sub-lethally damaged Listeria a selective two step en enrichment procedure performed with the samples is necessary.
Subsequently to the pre-enrichment the broth has to be heat treated to kill all present Listeria. The broth is then added to the wells of the micro titer plate at room temperature. Highly specific, purified antibodies selectively capture anyListeria antigens in the sample. The sandwich is completed by the addition of enzyme-labeled antibodies (conjugate) specific for Listeria spp.
The presence of Listeria is indicated when the substrate for the enzyme converts to blue color in the final performance step. The results can be read with a micro plate reader after stopping the enzyme reaction by adding sulfuric acid which will turn the blue color into yellow. Positive samples should be analyzed further for presence of L. monocytogenes (according to ISO 11290).
|Test Format||Micro titre plate with 96 wells (12 strips with 8 breakable wells each)|
|Standard Range||Positive and negative control|
|Sample Preparation||Selective two step enrichment in half strength Fraser broth/full strength Fraser broth|
|Incubation Time||1 h 30 min|
|Detection Limit||1 cell/25 g of sample which equals to 105 Listeria cells/ml after total enrichment time.|
|Cross Reactivity||38% to Staphylococcus aureus (neglectable if pre-enrichment has been performed regularly)|
|Shelf life||24 months (from date of manufacture) at 4 °C|
|Additional Information||RIDASCREEN® Listeria will detect all relevant Listeria species including strains of the human pathogenic member of the genus L. monocytogenes.|