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

The following are comments from the Allergen WG that may apply to the Gluten document:

Page 3, 3.14 Intermediate Precision : Include definition of RSDi [Allergen document added a note under this definition stating “For the purposes of this document, the subscript notation "i" will be used to indicate terms and estimators associated with intermediate precision. Estimation methods can be found in section 5.2.4.2.3.” In the gluten doc, the relevant section is 4.6] Added this same wording to the definition. Page 4, Definitions: Definitions for Precision, Repeatability and Reproducibility should site ISO 3534 2:2006 rather than ISO 5725-1, which has been updated [Allergen doc has made this change] Decision was to leave references to 5725-1. Page 4, 3.23 Precision : Add the word “obtained” [This is now “Closeness of agreement between independent test/measurement results obtained under stipulated conditions. (ISO 3534-2:2006)” in the Allergen doc] This change was not made. Page 4, 3.31 Reproducibility Conditions : Change ‘separate instruments’ to ‘different equipment’ [This definition reads “Observation conditions where independent test results are obtained with the same methods on equivalent test items in different laboratories with different operators using different equipment. (ISO 3534-2:2006, with minor modifications)” in the Allergen doc] Decision was to leave this as separate instruments, since in discussion some WG members felt that the term ‘different equipment’ could be interpreted as not allowing two independent labs to use the same model of an instrument. Page 5, Section 4.2: 'Residual' should be defined previously. Residuals should be expressed as OD values, not ppm, and should also include standard deviation. [Allergen document edited the second paragraph of this section to read “From the calibration curve function, determine the calculated concentrations for each of the standards. Calculate the residuals for each non-zero concentration standard. Residuals are the difference between the observed value and the predicted value for each dependent variable in the calibration curve. (Residual = observed value - predicted value.) Residuals should be calculated from the instrument response. For most quantitative food allergen methods, instrument response would be optical density (absorbance) values.”] Same edit was made for the gluten document, so the second paragraph now reads “From the calibration curve function, determine the calculated concentrations for each of the standards. Calculate the residuals for each concentration standard. Residuals are the difference between the observed value and the predicted value for each dependent variable in the calibration curve. (Residual = observed value - predicted value.) Residuals should be calculated from the instrument response. For most quantitative gluten methods, instrument response would be optical density (absorbance) values.” Page 7, paragraph 3 . Allergen document starts with a paragraph stating that “At least 4 concentrations per matrix, including a zero/blank, must be included in the study. One concentration should less than or equal to two times the stated LOQ for the method. Other concentrations should span the calibration