AOAC GFA Stakeholder Program Meeting Book (March 15, 2023)

4.1.8 Method Instructions …

Details should be provided on result interpretation. For example, in kits where color change is a factor, end users should be directed on when to call a result positive based on color intensity. In this area as well, pictorial examples are encouraged. Include details on the reporting of results (positive, negative, < > the CDC, detected/not detected at the CDC, etc.), name of method, the units (wheat protein, gluten, gliadin, etc.), and the method for converting all results to gluten values. The instructions must clearly outline any known limitations of the method, including any sources of gluten that are not detected by the method, any known under- or over-sensitivity to specific gluten sources, cross-reactivity or interference from any matrices, and information on specific fractions/proteins targeted. … Proposed New Text 4.1.8: The instructions must clearly outline any known limitations of the method, including any sources of gluten that are not detected by the method, any known under- or oversensitivity to specific gluten sources, cross-reactivity or interference from any matrices, and information on specific fractions/proteins targeted. Instructions shall also note that the extent of inhomogeneity of gluten across test portions is highly dependent on the specific processing conditions of food products. This inhomogeneity may lead to false negatives at gluten levels above the stated CDC as well as positives at levels far below the CDC. The results of the verification POD tests do not substitute for the kit users developing appropriate sampling plans based on the variance of gluten concentration within their specific products. Appropriate storage conditions must be provided. J ustification: Our extensive experience with quantitative gluten testing has shown that gluten concentration variation across test portions is the dominant source of variation in many matrices. Although the POD testing is useful for kit validation, kit makers and end users should be careful not to extrapolate POD data from the kit validation study to their own matrix and processing conditions.