Indirect competitive ELISA for determination of traces of peanut (Arachis hypogaea L.) protein in complex food matrices

An indirect competitive ELISA was developed allowing the detection of hidde n peanut protein residues down to 2 ppm (micorgrams per gram) in various fo ods. The high-titer, peanut-specific polyclonal antiserum used recognized p otentially allergenic proteins in both native and roasted peanuts. In the a bsence of a food matrix, extractable protein from roasted peanuts was detec ted at 104 +/- 13%. From various food items, peanut protein at greater than or equal to 13 ppm was recovered between 84 and 126%, and at 2 ppm of pean ut protein recovery was 143 +/- 6%. Intra- and interassay precision was <15 %. In 5 of 17 commercial food products without declaration of peanut compon ents, between 2 and 18 ppm of peanut protein was detected. This is the firs t assay based on commercially available reactants that allows the reliable determination of trace amounts of hidden peanut allergens in a variety of c omplex food matrices.