September 18, 2016, the AOAC Expert Review Panel (ERP) for Stakeholder Panel on Strategic Food Analytical Methods (SPSFAM)
Ethanol in Kombucha Methods, chaired
by Sneh Bhandari, Mérieux NutriSciences,
a First Action Official MethodSM
for ethanol in kombucha using gas
chromatography. The ERP agreed
that the method acceptably meets Standard
Method Performance Requirements (SMPRs®) developed and approved through
voluntary stakeholder consensus. Standards development activities for
the kombucha project are supported by AOAC Organizational Affiliates (OAs), as
part of the AOAC working group initiative.
“We were highly impressed by the
thoroughness and scrutiny of the methods,” said Justin Trout, COO/Co-Founder
of Health-Ade Kombucha, an AOAC OA supporting the kombucha working group. “That
type of responsible action is precisely why we came to AOAC in the first place.
It was wonderful to see so many sharp and caring minds in the room working to
solve our industry’s biggest problem.”
AOAC standards are needed for an
analytical method to measure the low levels of ethanol in kombucha. Since
kombucha may contain more than 0.5% alcohol by volume (ABV), some kombucha
breweries have elected to brew their kombucha under state beer or wine
licenses–while many have chosen to tightly control their production processes
and offer nonalcoholic beverages. Standards and methods are critical for
industry to build trust with customers, retailers, and distributers.
Submitted by NaturPro Scientific, a single-laboratory validation
(SLV) of a method is described for determination of ethanol in kombucha by
headspace gas chromatography-flame ionization detection (GC-FID). The method
uses headspace autosampler to introduce ethanol vapors into the gas
chromatograph. Ethanol from the sample is vaporized into the headspace
autosampler, thereby preventing some matrix interference. n-Propanol is used as an internal standard. Ethanol is estimated as
Precision was determined by
analyzing six replicates of each sample of commercial kombucha over a minimum
of 2 days. Accuracy was determined by testing duplicates at each of three spike
levels of pure ethanol into control kombucha over 3 days. The
method was shown to be applicable for determination of 0.1-3.3% ABV in aqueous
kombucha tea beverages.
In general, the ERP agreed that the method acceptably meets the
SMPR, with valuable method performance information provided, particularly for
accuracy and precision. In addition, the method is simple, straightforward, and
highly promising. The method was adopted by the ERP as First Action Official MethodSM 2016.12.
Full coverage appears in the November/December 2016
issue of Inside Laboratory Management.