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Casein ELISA Kit is intended for the quantitative determination of casein in raw as well as heat treated foods.

Casein ELISA Kit contains all the necessary reagents for extraction and quantitative determination of casein.

It is possible to determine up to 40/17 samples in duplicates (96-wells micro-titre plate/48-wells micro-titre plate) with the set Casein ELISA Kit.

Time required for the sample preparation and extraction: 1 hour (10 samples)
Time required for ELISA determination: 2 hours 50 min
Limit of detection (LOD): 0.24 ppm (mg/kg)
Limit of quantification (LOQ): 1.30 ppm (mg/kg)
Calibration scale range: 1.5 – 45 ppm (mg/kg)
Expiration time: 12 months (at 2 – 8 °C)

Milk is one of main allergenic foods, especially for children. Prevalence of this allergy differs in different countries; the incidence varies between 1 % and 3 %. Native milk and milk products contain protein allergens (see below) as there is no proof for the proposition that milk processing could change the protein structure to the extent of changing its allergenic properties. This is also the case with thermally processed milk. Cow’s milk contains 30 - 35 g proteins/litre. Its acidification to the pH value of 4.6 causes formation of 2 fractions – whey (20% content of proteins) and curd (80% content of proteins). The whey contains mainly beta-lactoglobulin (BLG), alpha-lactalbumine (ALA), bovine serum albumin (BSA), lactoferrin (LF) and immunoglobulins (Igs). The curd consists of casein (CAS) that occurs in 4 modifications – named Alpha s1, Alpha s2, Beta and Kappa.

A big advantage of SEDIUM CASEIN ELISA competitive assay is the ability to detect fragments of Alpha - casein molecules arisen during enzymatic treatment of milk. It was demonstrated that very small Alpha - casein fragments of the size several hundreds Da should be detected by SEDIUM CASEIN ELISA KIT.

The determination of casein is based on its immunochemical reaction with a specific antibody. CAS present in analyzed sample and CAS, having been marked with biotin prior to the analysis, react in the first step (incubation) with a specific antibody coated on the walls of wells, as arrayed in a micro-titre plate. As a net result, CAS is bound to the wells’ walls, while both, CAS of the sample and that marked with biotin, compete for access to binding spots of the antibody against CAS; these spots are limited in their count. After the wells are rinsed, the horse-radish peroxidase conjugated with streptavidin is added. After incubation the wells are rinsed again and the perioxidase that got bonded to the walls of the wells is detected by the addition of a chromogenic substrate (tetramethylbenzidine). The intensity of thus obtained colouration is inversely proportional to the concentration of CAS in calibrators, control samples and analysed samples.