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

4.3.3 Matrix / POD study The collaborator sites will perform the matrix / POD studies for each claimed gluten source in at least one of the incurred matrices for each matrix category claimed in the method developer study, following the rotation of claimed gluten sources shown in Tables 1 or 2, depending on the method claims. If the method developer study consisted of only individual matrices, rather than matrix categories, then the collaborator study will test at least one incurred matrix for every 5 matrices tested in the method developer study, as shown below: Since we (absolutely justified) put a lot of emphasis on the necessity to test incurred matrices, at least one incurred matrix tested by the independent laboratory for PTM and at least one incurred matrix tested in the collab study should also be prepared by an independent entity (according to a recipe provided by the method developer). Note Section 4 states that “ Ideally, test materials for the independent laboratory and collaborative studies should be prepared by an external entity independent from the method developer. In situations where an independent entity is unavailable, method developers may produce and distribute test materials if detailed information is provided on procedures used to prevent bias (preparation, coding, etc .)”