Enzyme immunoassay for the quantitative determination of Ovalbumin in food.
Background: Hen’s egg (Gallus gallus) is very rich of proteins and represents an important food source for humans. While proteins of egg yolk only have minor allergenicity, many proteins of egg white are known to be allergenic. In addition to lysozyme, ovomucoid ovotransferrin and livetin, ovalbumin represents the main fraction of the egg white allergens. Amongst others egg powder as well as pure ovalbumin is often used as fining reagent for wine. For allergic persons the consumption of ovalbumin represents a critical problem. Already very low amounts of the allergen can cause allergic reactions, which may lead to anaphylactic shock in severe cases. Because of this, ovalbumin allergic persons must strictly avoid the consumption of ovalbumin containing food. Non-declared addition of ovalbumin in food is hazardous for allergic people. Cross-contamination, mostly in consequence of the production process, is often noticed. Since July 1, 2012 the European Union requests allergen labeling for wine if milk or egg proteins are used during the production and are still present at a detection level of 0.25 mg/L or greater. Thus for the detection of ovalbumin residues, sensitive assay systems are required.
Ovalbumin ELISA represents a highly sensitive detection system for ovalbumin and is particularly capable of the quantification of ovalbumin residues in wine.
Description: The Ovalbumin quantitative test is based on the principle of the enzyme linked immunosorbent assay. An antibody directed against ovalbumin is bound on the surface of a microtiter plate. Ovalbumin-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 directed against ovalbumin 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 ovalbumin 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;
- Ovalbumin standards: 0, 25, 100, 250, 500 ppb;
- ELISA reader at 450 nm;
- Standard range: 25 - 500 ppb;
- Sensitivity analytical: 4 ppb.