Allergen determination in food: reference materials and traceability of results

Food allergens are more or less denatured mixtures of non-defined proteins in complex matrices. The most common technique to measure these proteins is an antibody-based system as, e.g., a commercial ELISA system which consists of an extraction procedure, suitable antibodies and a calibrator. Until now, only a few attempts to standardize these different ELISA systems were performed and the most promising way seems to be a standardization of the calibrator. It is shown that we have currently no methods to fully characterize these calibrators, which are always complex protein mixtures. This also means that the production of reference materials containing these calibrators is not possible. It is proposed to choose a different way because we will never have an unbroken traceability chain. As described in ISO 17511:2003 for the clinical area, one possibility could be the selection of a commercial preparation (e.g. skim milk powder) to which all test kit manufacturers will relate their results on and in a second step to select a reference method.