Munilla García et al. 2023 — Lead poisoning family outbreak from kombucha in ceramic containers, Ibiza
This case report describes an outbreak investigation by Balearic Islands food safety authorities following a family of four presenting with markedly elevated blood lead levels at Hospital Can Mises, Ibiza. The affected individuals were producing and selling kombucha fermented in unglazed or improperly glazed ceramic vessels. Lead concentrations in the kombucha samples rose dramatically with fermentation time and storage: 0.95 mg/kg at 14 days fermentation (unpackaged), 7.1 mg/kg at 19 days (unpackaged), and 47 mg/kg in the packaged ready-to-sell product. Lead migration from the ceramic commercial containers under acetic acid simulant (4% acetic acid, 24 h, 22°C) ranged from 5.8 to 73 mg/L. The father, who consumed more than one glass daily, had blood lead of 3,324 µg/L; his wife 1,349 µg/L; two children (aged 8 and 9) 487 and 551 µg/L. No EU or Spanish maximum level exists for lead in kombucha, which the authors flag as a regulatory gap. The ceramic containers’ supplier lacked required sanitary registration. Risk assessment used EFSA Benchmark Dose Lower Confidence Limits (BMDL01 for developmental neurotoxicity 0.5 µg/kg bw/day; BMDL01 cardiovascular 1.5 µg/kg bw/day; BMDL10 nephrotoxic 0.63 µg/kg bw/day).
Key numbers
Kombucha lead concentrations (ICP-MS, Agilent 7900):
- 14-day fermentation, unpackaged: 0.95 mg/kg (950 ppb)
- 19-day fermentation, unpackaged: 7.1 mg/kg (7,100 ppb)
- Packaged, ready for sale: 47 mg/kg (47,000 ppb)
Lead migration from ceramic containers (4% acetic acid simulant, 24 h, 22°C):
- Commercial sale containers: 5.8–73 mg/L
- Fermentation containers: values reported but not extracted (commercial containers most alarming)
Raw materials tested:
- Drinking water and sugar: <0.02 mg/L (below LOQ)
- Three tea varieties: lead detected (concentrations not extracted from figures)
- SCOBY: lead detected at high concentration (not numerically extracted)
Blood Pb levels in affected family:
- Father (52 years): 3,324 µg/L
- Wife: 1,349 µg/L
- Child 1 (8 years): 487 µg/L
- Child 2 (9 years): 551 µg/L
EU regulatory context: EU Regulation 1881/2006 on contaminants (as amended by 2023/465 and others) sets maximum levels for Pb in beverages but kombucha is not explicitly listed. Lead migration limits for ceramic food contact materials are established under Spanish Real Decreto 891/2006 and EU harmonised rules; the authors identify inadequacy of existing limits for acidic fermented beverages.
Methods (brief)
Investigative case report by Balearic Islands food safety authorities (Servicio de Seguridad Alimentaria). Pb determination: ICP-MS (Agilent 7900) with Micromist nebuliser, collision cell mode (helium); Ir-193 as internal standard. Four-point external calibration. Laboratory accredited under UNE-EN ISO/IEC 17025 (ENAC). Migration testing per Real Decreto 891/2006 and UNE 126301:2003 using 4% acetic acid simulant at 22±2°C for 24±0.5 h. No LOQ stated for the final kombucha product measurements; LOQ for water matrices: 0.02 mg/L. n=5 samples total (raw materials, fermentation-stage, packaged product, containers).
Implications
Certification: This is a food-contact-material contamination event, not an ingredient-level occurrence. The route is lead leaching from improperly fired or glazed ceramic containers under acidic conditions. The kombucha’s organic acid content (acetic acid, gluconic acid) drives high migration. Directly relevant to HMT&C’s position on artisanal and small-batch beverage certification: ceramic container provenance and food-contact certification must be verified. Relevant also for any fermented beverage product category.
Courses: Illustrates the food-contact-material pathway for heavy metal contamination in fermented beverages. Demonstrates the regulatory gap for novel beverages like kombucha. The dramatic time-dependent increase from 0.95 to 47 mg/kg over the storage/fermentation timeline is a key teaching illustration of accumulative migration.
App: Not directly applicable to ingredient-level risk scoring. The lead in this case is from the container, not the ingredients. App risk scoring should flag artisanal or home-produced fermented beverages as outside the ingredient-profiling model.
Microbiome: Not applicable.