Expert Review Panel for Kombucha Tea

7. Any general comments about the method? * This is an accurate and precise method and I praise the authors for the work and use of novel instrumentation to address some issues for this challenging matrix. The data presented are intriguing because it also shows how slight changes in the method cause results to fall outside SMPR. For example, the internal standard (deuterated ethanol) diluted in water versus a salt-buffer solution had a repeatability of 9%, higher than the SMPR of 4%. Decreasing column temperature by 10 degrees led to a repeatability of 9%, versus 0.9% reported with the optimized method. The data suggests that there are good reasons to re-validate a method whenever slight modifications are made.

Final Recommendation Do you recommend this method be adopted as a First Action and published in the Official Methods of Analysis of AOAC INTERNATIONAL? Please specify rationale. * I recommend the method be adopted as First Action due to the robustness of the method. I would also recommend additional precision data on higher alcohol kombucha samples to be generated.