Development of an enzyme-linked immunosorbent assay for peanut proteins using chicken immunoglobulins

Chickens were immunized with protein extracts from respectively roasted Virginia and raw Runner peanuts. Immunoglobulins were conveniently extracted from the egg yolk in order to evaluate the immune response. Antibodies towards roasted peanuts were subsequently used in a competitive indirect immunoassay for the quantification of peanut proteins in foods. Various assay parameters were proven to have a significant influence on the assay sensitivity. Peanut proteins could be detected in foods at least down to a 1 ppm level. The isolated immunoglobulins proved to be very specific towards peanut proteins. Immune reaction of the antibodies varied, however, depending upon the peanut variety and the processing history of the peanuts themselves. In addition, experiments on spiked food matrices showed that careful selection of the extraction buffer is of prime importance as well. The developed immunoassay can be used as a semi-quantitative tool to confirm the presence or absence of a group of important allergic proteins in foods.