Enzyme immunoassay for the quantitative determination of Brazil Nut in food.
Background: The Brazil nut tree (Bertholletia excelsa) belongs to the family of Lecythidaceae. The amount of protein in brazil nut is about 14%. Some of these proteins are known for being allergenic, like the 2S albumin Ber e 1 or the 11S legumin Ber e 2. Compared to other nuts the allergenic potential of brazil nuts is still slightly characterized. Brazil nut allergies are relatively seldom, but can be very distinct in particular cases. For brazil nut allergic persons hidden brazil nut allergens in food are a critical problem. Already very low amounts of brazil nut can cause allergic reactions, which may lead to anaphylactic shock in severe cases. Because of this, brazil nut-allergic persons should strictly avoid the consumption of brazil nut containing food. Cross-contamination, mostly in consequence of the production process, is often noticed. This explains why in many cases the existence of brazil nut residues in food cannot be excluded. For this reason sensitive detection systems for brazil nut residues in foodstuff are required. Brazil nut ELISA represents a highly sensitive detection system for brazil nut and is particularly capable of the quantification of residues in cookies, cereals, ice-cream, chocolate and sausage.
Description: The Brazil nut quantitative test is based on the principle of the enzyme linked immunosorbent assay. An antibody directed against brazil nut proteins is bound on the surface of a microtiter plate. Brazil nut 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 brazil nut 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 terminated by the addition of a stop solution, and the colour turns yellow. The yellow colour is measured photometrically at 450 nm. The concentration of brazil nut 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;
- Brazil nut Standards: 0, 1, 4, 10, 40 ppm;
- ELISA reader at 450 nm;
- Standard range: 1 - 40 ppm;
- Sensitivity analytical: 0.2 ppm.