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?

The method is written very clearly. Given the detail included regarding method development and validation, I would not consider the submission package concise. However, the method details could be extracted into a concise stand-alone document.

The supporting information includes extensive method development and validation data, in some cases exceeded the expectation of the SMPR. This additional data added significant amount of credibility to the method. The method demonstrates strong performance with a number of certified standards. The majority of the method validation was performed with a tea blank that is not true kombucha. Certified standards were analyzed in water and a beer standard was also used, both of which performed well. Limited validation of the method was performed with actual kombucha. Based on the method development, one would expect the method to perform equally across the matrices, however it was not explicitly demonstrated. A GC-MS approach is highly suitable for the quantitation of ethanol in beverages. This method demonstrates thorough development and optimization for quantitation of ethanol in liquid samples. It is weaker with regard to validation in kombucha matrix, but has potential to be highly applicable and meet all requirements.

7. Any general comments about the method?

Recommendation for the Method

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, I recommend this method to be adopted as a First Action. The SPME-GC-MS technology is highly suitable for the analysis of ethanol in kombucha, and I believe that additional inter-laboratory validation will prove its performance. Not all Method Performance Requirements were determined in a kombucha matrix or in the same vocabulary as the SMPR, but the method appears to meet nearly all requirements.