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

4.1.6 Robustness study The method developer, in conjunction with the AOAC or other independent validation manager, is expected to make a good faith effort to determine which, and to what magnitude, parameters are most likely to vary in the hands of an end user. Each parameter should be varied both up and down by at least 20%. These parameters should be tested in a factorial or Plackett-Burman design, as described in Annex D. Robustness should be analyzed with a blank and a sample at the lowest CDC for one claimed gluten source, in a single incurred matrix. The matrix chosen should be one of the more challenging matrices (most highly processed) from the Matrix/POD study. Test ten biological replicates for each factorial pattern. POD should be calculated for each factorial pattern, and analyzed as described in Annex D. Data should be recorded in a table that describes each individual parameter variation, the individual results of each of the ten replicates for each factorial pattern, and the POD for each factorial pattern. The results of the statistical analysis should be reported in a separate table. Any parameter change that has a significant effect on the POD (p < .05) should be reported in the method instructions. Page 7 – “biological replicates” This is still confusing to me. “Test ten biological replicates for each factorial pattern” ?? What is a “factorial pattern?” I think you mean “factorial combination” or maybe “factorial treatment combination” I would replace with the following: “Analyze ten replicate test portions from the same test material for each factorial treatment combination.” Page 7 – “POD should be calculated for each factorial pattern.” I suppose you could do it that way – better to just say “Experimental results should be calculated as described in Annex D.”