AOAC GFA Stakeholder Program Meeting Book (August 27, 2023)

Selectivity Studies The claimed gluten sources (wheat (all Triticum species and Triticale), rye, barley and/or oats) should all produce mean recovery values that comply with the relevant method performance requirements (e.g., AOAC Specific Method Performance Requirements (SMPR)). In the absence of an applicable SMPR, an expert review panel will evaluate the study data according to their expert opinions. With respect to recovery, while ideal mean recovery values are from 80-120%, for single-gluten-source validations values of 50-150% can be acceptable. (Abbott et al 2010). For multiple gluten source validations (e.g., wheat, rye and barley), values of 50-200% can be acceptable at the discretion of the expert review panel (AOAC SMPR 2017.021). In the event that the confidence interval of the mean does not fall within the specified recovery range, the test material may be retested in additional test portions, and a new confidence interval calculated, to qualify as a gluten source quantified by the method. All data must be reported, included any testing done on different grain sources and varieties, and retests must be explained. Any gluten sources that do not meet these criteria cannot be claimed, and must be reported in the method instructions. A method claiming wheat must give a positive response to all listed Triticum species and Triticale, otherwise a claim for the specific Triticum species must be made. For methods claiming any Triticum species, only common wheat ( Triticum aestivum ) should be used in all other studies described in this guidance. 4.6 Selectivity Studies PAGE 9 “..should all produce mean recovery values…” Is mean an average of all spikes all levels? Second paragraph: “A method claiming wheat must give a positive response to all listed Triticum species and Triticale, otherwise a claim for the specific Triticum species must be made.” “Positive response” seems to be qualitative. Recommend something more like “..must give a value above the LOD at 20 ppm.” PAGE NINE – 4.6 ACCEPTANCE CRITERIA FOR SELECTIVITY AND MATRIX STUDIES – SELECTIVITY STUDIES