Overview
Tandhanskul and colleagues (Theophane Venard School of Food Biotechnology and Innovation, Assumption University of Thailand; Kagawa University Graduate School of Agriculture, Japan) review kombucha as a functional beverage that delivers postbiotics, parabiotics, and bioactive metabolites (the authors’ term: “metabiotics”). The review’s primary subject is fermentation microbiology, organic-acid and polyphenol chemistry, vitamin and mineral content, antioxidant and antimicrobial activity, sustainability of alternative substrates, and food-safety concerns. Heavy-metal content enters the review in three narrow ways: as cited mineral-profile measurements (Bauer-Petrovska and Petrushevska-Tozi 2000 [ref 102], section 4.3) including lead (Pb) 0.005 µg/mL, chromium (Cr) 0.001 µg/mL, Co 0.004 µg/mL, cadmium (Cd) undetected, and a statement that fermentation increases Cu, Fe, Mn, nickel (Ni), Zn but not Co; as two cited case reports of lead intoxication from kombucha brewed or stored in lead-glazed ceramic vessels (Sabouraud et al. 2009 [ref 187]; Phan et al. 1998 [ref 188]); and as a passing mention of SCOBY bacterial cellulose as a heavy-metal biosorbent citing Pb, Ni, and tea-fungus biosorption studies (refs 13–15). The review contributes no new measurements and frames kombucha contamination as primarily a vessel-leaching and food-safety practice issue rather than an ingredient-occurrence issue.
Key numbers
This is a narrative review with no new measurements. All values reported below are reproduced from cited primary studies; the review itself does not present pooled or independently verified data.
Mineral profile (review section 4.3, p. 9, citing Bauer-Petrovska and Petrushevska-Tozi 2000 [ref 102])
The review reproduces a kombucha mineral profile from a single underlying study, expressing values in µg/mL:
| Element | Concentration | Notes |
|---|---|---|
| Co | 0.004 µg/mL | lowest of the reported elements |
| Mg | 0.462 µg/mL | highest of the reported elements |
| lead (Pb) | 0.005 µg/mL | review notes “acceptable limit should not exceed 70–100 µg/mL in adults [ref 126]“ |
| chromium (Cr) | 0.001 µg/mL | review notes “the maximum concentration of 0.05 mg/L (50 ppb) is allowed in drinking water [ref 127]“ |
| cadmium (Cd) | undetected | qualitative |
Other essential and trace metals — K, Mn, Cu, Fe, Mg, fluoride — are named but not numerically extracted in the review. The review states (section 4.3): “Fermentation has been shown to increase levels of some minerals (Cu, Fe, Mn, Ni, Zn), but not cobalt [ref 102] which could be from SCOBY or additives from fermentation.”
The review reports a fluoride range of 0.42–0.93 mg/L across tea types, attributed to Jakubczyk et al. [ref 103].
Food-safety section (review section 7, p. 16, citing case reports)
The review cites two case reports of lead intoxication from kombucha brewed in lead-glazed ceramic pots, plus one kefir case, attributed to references [187] (Sabouraud et al. 2009 — environmental lead poisoning from lead-glazed earthenware used for storing drinks, Rev. Médecine Interne) and [188] (Phan et al. 1998 — lead poisoning from drinking kombucha tea brewed in a ceramic pot, Med. J. Aust.). The review’s own language: “In all cases, lead-glazed ceramic pots have been used for fermentation, suggesting that acids produced during fermentation eluted lead from the glaze. Lead is also known to be eluted from crystal decanters to wine and spirits contained in it, thus emphasizing the importance of standardizing manufacturing practices to avoid such pitfalls.” No quantitative blood-lead or kombucha-lead concentrations are reported in this section of the review.
Bacterial cellulose biosorption (review section 2, p. 3, citing biosorbent studies)
The review states the SCOBY bacterial cellulose biofilm “has been investigated as a bioadsorbent for heavy metals [refs 13–15]” without reporting quantitative removal capacities. The cited primary studies are:
- Mousavi et al. 2018 [ref 13] — Pb(II) removal from synthetic wastewater using kombucha SCOBY and graphene oxide/Fe3O4, Phys. Chem. Res. 6, 759–771.
- Mousavi et al. [ref 14] — Separation of Ni(II) from industrial wastewater by kombucha SCOBY as a colony consisted from bacteria and yeast, Acta Chim. Slov. 66, 865–873.
- Najafpour et al. 2020 [ref 15] — Study of heavy metals biosorption by tea fungus in kombucha drink using central composite design, J. Food Compos. Anal. 86, 103359.
Drinking-water cap noted in review (review section 4.3, citing WHO 1996 [ref 127])
The review cites the WHO drinking-water guideline of 0.05 mg/L (50 µg/L) for chromium as the comparator for the Cr 0.001 µg/mL value reported above. The review’s lead comparator (“acceptable limit should not exceed 70–100 µg/mL in adults”) cites Wani et al. 2015 [ref 126]; see Verification notes below — the units as stated in the review are inconsistent with standard adult blood-lead reference levels and appear to be a unit-of-measure error in the review text itself.
Evidence Fitness
This source is a narrative review of kombucha as a source of postbiotics and metabiotics. Heavy-metal content enters only as cited values, not as new measurements. It contributes no primary occurrence data to Kombucha (Tea-Based) and is not eligible as a pooling-engine input for any percentile work on the kombucha row. It functions as: (1) a pointer to the Bauer-Petrovska and Petrushevska-Tozi 2000 underlying mineral-profile paper, which should be ingested directly if and when kombucha occurrence data are needed; (2) corroboration that the lead-glazed ceramic vessel pathway documented quantitatively in Family outbreak of lead poisoning associated with the consumption of kombucha manufactured and marketed in ceramic containers is recognised in the kombucha review literature and cited back to two earlier case reports; and (3) a reference list pointing to three SCOBY bacterial cellulose biosorbent studies (Mousavi 2018 Pb, Mousavi Ni, Najafpour 2020 multi-metal) that sit outside HMI’s primary occurrence-data scope but are relevant for remediation and food-contact framing. Reported public evidence label: Context only.
Methods (brief)
Narrative review (MDPI Beverages, Volume 11, Issue 6, article 173). No systematic search strategy, database list, inclusion/exclusion criteria, deduplication procedure, or PRISMA flow diagram is stated. The Data Availability Statement (p. 17) reads “No new data were created or analyzed in this study. Data sharing is not applicable to this article.” The review compiles values from 192 cited references covering kombucha microbiology, organic-acid chemistry, polyphenol chemistry, vitamin and mineral content, antioxidant and antimicrobial activity, anticancer and antidiabetic activity, gut–brain axis, sustainability of alternative substrates, circular bioeconomy, and food-safety case reports. No analytical instrument or laboratory methodology is reported because the review presents no original measurements.
The cited mineral-profile values (Bauer-Petrovska and Petrushevska-Tozi 2000 [ref 102]) are reproduced as the underlying paper published them, in µg/mL units; the review does not state the underlying paper’s analytical instrument, sample preparation, detection limits, sample size, fermentation conditions, or tea substrate. The cited lead-poisoning case reports (Sabouraud 2009 [ref 187]; Phan 1998 [ref 188]) are reproduced as the review summarises them, without quantitative blood-lead or kombucha-lead concentrations.
Implications
- Certification: contributes no direct occurrence data to Kombucha (Tea-Based). The two referenced lead-poisoning case reports are useful corroboration of the food-contact-material vessel-leaching pathway already documented quantitatively in Family outbreak of lead poisoning associated with the consumption of kombucha manufactured and marketed in ceramic containers; the contamination route is acidic fermentation product eluting lead from lead-glazed ceramic vessels rather than ingredient occurrence. The Bauer-Petrovska 2000 mineral profile (Pb 0.005 µg/mL = 5 µg/L; Cr 0.001 µg/mL = 1 µg/L; Cd undetected) sits in a non-ceramic-vessel kombucha sample at the low-µg/L scale, consistent with finished-tea occurrence rather than vessel migration; the underlying paper should be ingested directly for a defensible kombucha-row contribution.
- Courses: useful as a teaching reference for the food-safety section on kombucha vessel-leaching contamination and as an entry point to SCOBY bacterial-cellulose biosorbent applications outside the HMI primary scope.
- App: contributes no per-product concentration values; downstream consumers should source values from the original Bauer-Petrovska 2000 paper and the Munilla García 2023 case-report ingest.
- Discovery: the references most directly relevant to HMI primary scope are ref [102] Bauer-Petrovska and Petrushevska-Tozi 2000 (Int. J. Food Sci. Technol., kombucha mineral profile), ref [187] Sabouraud et al. 2009 (Rev. Médecine Interne, lead-glazed earthenware lead poisoning), and ref [188] Phan et al. 1998 (Med. J. Aust., lead poisoning from ceramic-pot-brewed kombucha). The three SCOBY biosorbent references (refs [13–15]) are remediation-scope and not HMI primary literature.
Provenance notes
Open-access article distributed under CC BY 4.0 (license declaration on p. 1 of the PDF). Received 17 June 2025; revised 17 November 2025; accepted 20 November 2025; published 3 December 2025. Citation: Tandhanskul, A.; Krungkaew, S.; Li, L.; Kham, S.A.; Yonekura, L. Kombucha as a Sustainable Source of Metabiotics: Potential, Applications, and Future Perspectives. Beverages 2025, 11, 173. https://doi.org/10.3390/beverages11060173. Academic Editor: Antonio Alfonzo. Funding statement: “This research received no external funding.” Conflict-of-interest statement: “The authors declare no conflicts of interest.” Accessed via the Manual Fetch Discovery autopilot.
Evidence tier set to C. The source is a narrative review without systematic methodology, presents no new measurements, and reproduces a single mineral-profile point estimate per element from a single 2000-vintage underlying study (Bauer-Petrovska and Petrushevska-Tozi 2000 [ref 102]). The review’s scope is fermentation chemistry and functional-food positioning, not heavy-metals occurrence; heavy-metal content is incidental to its subject and not independently verified.
Related evidence
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