AOAC Gluten Quantitative Validation Guidance-Round 1(Nov 2023)

Page 8, Section 4.5, Recovery : Clarification on “expected” concentration, and calculating percent recovery. Across multiple levels? If across multiple levels report recoveries by level, and/or by slope or other “averaging”? Edited to include estimation of recovery by slope and per concentration – “For each claimed matrix and gluten source, plot the observed concentration vs. expected concentration for all levels, and perform a linear regression to determine the slope and confidence interval of the slope. Also calculate and report the recovery and confidence interval at each concentration, by taking the mean of the test portion values and calculating the recovery.” Page 9, Section 4.6, LOQ : Delete "for a particular food allergen", as the document deals with gluten. Page 9, Section 4.6, LOQ : Delete "for a particular food allergen", as the document deals with gluten Deleted Page 9, Section 4.6, LOQ : LOQ, 5 th paragraph: Period and space after maximum RSDi of 30%. Edited Page 9, Section 4.6, Matrix Studies : “..should all produce mean recovery values…” Is mean an average of all spikes all levels? More information was provided on calculating this per linear regression and per concentration, so this section now reads “…should all produce recovery values (determined as the mean value by weighted linear regression, with the associated confidence intervals) that comply with the relevant method performance requirements…” Page 9, Section 4.6, Matrix Studies: should we leave in the section regarding the need for the confidence interval to fall within the acceptance criteria This criteria remains, but information has been provided to handle instances where the confidence interval may not fall within the specified range – “In the event that the confidence interval of the recovery mean as determined by weighted linear regression 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.” Page 9, Section 4.6, Matrix Studies 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.” This whole sentence was deleted, replaced by “Each claimed gluten source (wheat (all Triticum species and Triticale), rye, barley and/or oats) in each matrix (or pooled across matrices if all matrices show equivalent recoveries) should all produce recovery values (determined as the mean value by weighted linear regression, with the associated confidence intervals) that comply with the relevant method performance requirements (e.g., AOAC Specific Method Performance Requirements (SMPR)).”