Expert Review Panel for Kombucha Tea

In most cases, terminology is used appropriately. In some cases, the term reproducibility is used interchangeably with repeatability. In this study, reproducibility is defined as two instruments and analysts, and it was not clear whether these were in different labs with different sample prep/procedures areas, or within the same lab.

4. Safety precautions - No information was given on safety precautions.

Review of Supporting Information 1. Are the definitions specified in the SMPR used and applied appropriately in the supporting documentation (manuscripts, method studies, etc...)? If not, please explain the differences and if the method is impacted by the difference. * Definitions are used appropriately 2. Is there information demonstrating that the method meets the SMPR Method Performance Requirements using the Reference Materials stated in the SMPR? If not, then specify what is missing and how this impacts demonstration of performance of the method. * The information demonstrates that the method is appropriate for the reference materials ethanol. The percent recovery was between 98 and 100%, within the SMPR of 97% to 102%. The analytical range for the method was the same as in the SMPR, 0.1% to 2.0%. The LOQ for buffer spiked with ethanol was 0.03% ABV, lower than the SMPR LOQ of 0.05%. %. The RSD of 4 spiked samples were between 1-3%. The mean % difference of 13 duplicates of high alcohol kombucha was 5.1%, similar to the RSD of 4%. Reproducibility was also presented as the same method using certified reference materials (beer and ethanol-water) on different instruments and different analysts, and the RSD was 3-5%. 3. Is there information demonstrating that the method performs within the SMPR Method Performance REquirements table specifications for all analytes in the SMPR applicability statement? If not, please specify what is missing and whether or not the method's applicability should be modified. * I am not sure whether the repeatability calculation given for the higher alcohol kombuchas is sufficient, since it is not the result of a standard deviation calculation. I would be open to discussion on this part. General Submission Package 1. Based on the supporting information, were there any additional steps in the evaluation of the method that indicated the need for any additional precautionary statements in the method? * Based on the ruggedness data, I would recommend to include ruggedness data within the method, along with a reminder that changes to the method should be re-validated as part of internal method acceptance procedures.