BS EN 15842 pdf free download

BS EN 15842-2019 pdf free download.Foodstuffs – Detection of food allergens – General considerations and validation of methods.
4 General aspects for methods and reference materials in food allergen analysis 4.1 General considerations A major challenge for allergen analysis consists in achieving measurement results which are comparable across different measurement methods and laboratories. The key requirement to ensure such comparability is the metrological traceability of all measurement results to a common reference, which serves as an anchor or benchmark for scaling the data. For establishing metrological traceability an agreement is needed on the definition of the measurand, i.e., on the quantity intended to be measured (JCGM 200 [16]). In order to support current risk assessment and EU legislation, the quantity for reporting the content of an allergen in food should be the mass (mg) of total allergenic ingredient protein per mass (kg) of food. Consequently the International System of Units (SI), namely the kilogramme, is used as one component of the ultimate reference for measurement results on allergens. However, the common reference as defined above can only be realized for each allergen via reference measurement systems, consisting of reference methods and reference materials. In that concept the reference method is forming the highest metrological level of the traceability chain. It needs to be well described and specific enough to ensure that results can be reliably reproduced within a prescribed measurement uncertainty over time and space. The reference method shall be applied in allergen analysis for characterizing candidate reference materials, intended to be used as primary calibrants, and for establishing conversion factors allowing the transformation of results obtained by different methods to the common measurands scale. Testing for the presence and amounts of allergens in food may be often performed by using screening methods. At the discretion of the laboratory or on customer request, the measurement results from such screening methods may be checked by using confirmatory methods. The latter should be validated according to standards, such as EN ISO/IEC 17025, before their application. As the measurand defined above is not directly accessible by any currently available measurement method, the whole measurement process from the laboratory sample to the final result should be appropriately designed for being able to express the measurement results in a uniform manner. Specific consideration for that are listed in the following clauses and subclauses.
4.2 Reference material The reference materials described hereafter are primarily intended for the calibration and validation of analytical methods for the determination of allergenic commodities in food products and not necessarily for the determination of a specific allergen. A metrological traceability chain should be established for assigning certified values to matrix samples. This traceability chain shall include well characterized primary standards, which are designated or widely acknowledged as having the highest metrological quality. Standards of lower metrological order (secondary standards, matrix materials) should be traceable to the primary standard, but need to be commutable to the samples to be analysed (concerning expected concentration of the analyte, matrix and processing history, etc.). Matrix reference materials (secondary standards), which contain the analyte (allergenic food) in a similar chemical state and in a matrix similar to the test sample, are needed for the calibration and validation of routine testing methods. Procedures for developing in-house reference materials have been proposed by IUPAC [17]. Generally, the homogeneity and stability of any reference material should be guaranteed and stated. It is recommended to provide as much information about the origin and features of the reference material as possible (e.g. processing history, variety, geographical origin, preparation protocol, etc.). NOTE In case of the lack of accepted reference materials, it is common to use the same material for consistent control of method and laboratory performance.
4.3 Reference method A reference method for the determination of allergenic food commodities should be independent of any technological influences and matrix effects, in order to reliably measure one or more property values characteristic of the allergen concerned. The reference method’s accuracy and precision should be commensurate with its intended use and permit the characterization of a reference material. Reference materials may be used to calibrate instruments, to determine trueness/bias of a method (validate a method) and to assign values to testing materials. In case of bias, checking the results obtained from a CRM by using a certain analytical method may be compared to the certified property value. If the absolute difference of the two sets of values (obtained values and certified value) exceeds the expanded uncertainty of this difference, the analytical method is considered to be biased (one or more systematic errors occurred). 5 Guidance to the user for selection of methods
5.1 General The specificity of particular food allergens and detection methods can vary considerably. It is therefore important to ensure that the chosen method(s) provide the desired specificity. The following guidance can be useful. NOTE 1 Most ELISA methods measure protein(s) or parts of proteins specific for the allergenic component. However, typically not all allergenic parts of an allergenic compound are detected by any single assay. No statement is possible regarding the presence of other allergenic parts not targeted by the assay. If fragments from one particular allergen are detected by mass spectrometry, other relevant allergens cannot always be detected as well. These possibilities can be of relevance for interpretation of results obtained on compound food products containing isolated protein fractions derived from allergenic commodities, in particular in case of a negative signal. Molecular biology methods detect DNA indicating the presence of an allergenic commodity. Depending on the processing grade of the food a positive test result of a molecular biology method will correlate with the presence of the potentially allergenic class of substances, i.e. protein. When purified fractions of a food are used in a compound food product (e.g. processed oils or starch), there is a possibility the DNA-based results will not coincide with the actual presence of protein-based allergens. 5.2 Immunoassay based methods Proteins can be detected by the application of mono- or polyclonal antibodies. The degree of affinity of the antibodies for the protein will depend on the protein conformation after extraction. Specificity of the used antibody needs to be demonstrated (e.g. no cross-reactivity).BS EN 15842 pdf download.