Expert Review Panel for Kombucha Tea

4. Based on the supporting information, is the method written clearly and concisely? If no, please specify the needed revisions. 5. Based on the supporting information, what are the pros/strengths of the method? 6. Based on the supporting information, what are the cons/weaknesses of the method?

Yes

Applicability to the wide range of matrixes; excellent sensitivity and accuracy; ease of sample pre and use

Requires spectrophotometer; cost of the kit; doesn't seem to be high throughput

7. Any general comments about the method?

1. Kombucha has some unique compounds such as gluconic acid. Can the acids' interference be tested? 2. ACQ CRMs (page 4 of 34) seem to have identical concentration. Is it a typo? 3. It would be interesting to see stability/levels of ethanol in kombucha measured at room temperature over time. 4. %abv concentration sometimes are written along g/L and sometimes not. I recommend to be consistent and always express all concentrations in terms of %abv along with g/L. 5. The kit insert doesn't mention conversion to % abv.

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.

Yes. The analytical range, LOQ, accuracy, and precision conform to those in SMPR. In addition multiple additional tests were perform to characterize method's robustness, specificity, interferences and sample stability.