Enzyme immunoassay for the quantitative determination of bovine milk protein in food.
Background: Bovine milk belongs to the most important allergenic food ingredients especially for children. Already very low amounts of bovine milk can cause allergic reactions, which may lead to anaphylactic shock in severe cases. Because of this, milk allergic persons must strictly avoid the consumption of milk or milk containing food. In particular the presence of hidden milk proteins such as in sausage, cookies, convenience food or beverages represent a critical problem for milk allergic persons. According to EU Directive 2003/89/EG the addition of bovine milk has to be labeled. For the detection of bovine milk in foodstuffs, sensitive detection systems are required.
Approximately 80 % of bovine milk proteins are caseins. beta-Lactoglobulin, the major allergen of whey, represents further 10 % of the total protein.
Milk ELISA represents a highly sensitive detection system for milk proteins based on NIST 1549 reference material. The test is likewise capable of the quantification of casein and beta-lactoglobulin residues in food and is validated for cookies, bread crumbs, sausage, orange juice, wine, soy products and chocolate.
Description: The Milk quantitative test is based on the principle of the enzyme linked immunosorbent assay. An antibody mixture is bound on the surface of a microtiter plate. Milk protein containing samples or standards are given into the wells of the microtiter plate. After 20 minutes incubation at room temperature, the wells are washed with diluted washing solution to remove unbound material. A peroxidase conjugated second antibody mixture directed against milk proteins is given into the wells and after 20 minutes of incubation the plate is washed again. A substrate solution is added and incubated for 20 minutes, resulting in the development of a blue colour. The colour development is inhibited by the addition of a stop solution, and the colour turns yellow. The yellow colour is measured photometrically at 450 nm. The concentration of milk proteins is directly proportional to the colour intensity of the test sample.
- The kit contains reagents for 96 determinations;
- Microtiter plate consisting of 12 strips with 8 breakable wells;
- Milk protein Standards: 0, 0.4, 1, 4, 10 ppm;
- ELISA reader at 450 nm;
- Standard range: 0.4 - 10 ppm;
- Sensitivity analytical: 0.05 ppm.