Collaborative trial validation of RT-PCR methods for the detection and quantification of the allergenic foods fish and peanut

The analysis of food for allergens is an inherent part of consumer protection against health risks. Before application, these methods require validation by collaborative studies to ensure comparable results between laboratories. In this article, we present results of collaborative trial studies for validating RT-PCR methods for the detection and quantification of two food allergens, fish and peanut. Reference materials of different food matrices, spiked with fish and peanut, respectively, were analysed. Defined food matrix DNA standards (fish, peanut) as well as copy number based DNA solutions (fish) were applied for calibration and quantification. A limit of detection of approximately 10–20 mg/kg dried fish (i.e. approx. 50 mg fresh weight/kg) could be confirmed within a collaborative trial performed by 13 participating labs. Trueness and precision data were comparable to former collaborative studies suggesting that quantification is possible, if the fish species is known and appropriate calibration material is available. For peanut, we used a multicopy target-sequence, which allows a very sensitive detection of this allergen. Within the collaborative trial of 14 laboratories, a peanut concentration of 0.5 mg/kg (i.e. approx. 0.1–0.2 mg peanut protein/kg) could be detected reliably in a processed cookie matrix. The method revealed acceptable trueness and good precision data and is therefore suitable for quantification of the allergenic ingredient peanut. Both methods will be included into the Official Collection of Methods of Analysis in Germany in 2019 as a national standard method.