EFSA FAF Panel 2022 — Safety evaluation of buffered vinegar as a food additive
The EFSA Panel on Food Additives and Flavourings issued this scientific opinion following an application to authorise buffered vinegar as a preservative food additive in 24 food categories under EU Regulation (EC) No 1333/2008. Buffered vinegar is produced by adding sodium/potassium hydroxides and/or carbonates to food-grade vinegar; its primary constituents are acetic acid and its salts. The Panel concluded there is no safety concern at the proposed maximum/typical use levels; however, it could not conclude on safety at quantum satis because resulting exposure cannot be estimated. Critically for this wiki, the EFSA opinion includes a risk assessment of heavy metal impurities (As, Pb, Cd, Hg) in the proposed food additive, providing both specification limits and actual batch measurement data, as well as reference points and tolerable intakes against which estimated exposures were compared.
Key numbers
Proposed specifications for toxic elements in buffered vinegar (Table 1 of opinion):
- Arsenic (As): NMT 1 mg/kg
- Lead (Pb): NMT 0.5 mg/kg
- Mercury (Hg): NMT 0.5 mg/kg
- Cadmium (Cd): NMT 0.5 mg/kg
Actual batch measurement data (ICP-MS, USP 233, 5 batches each of liquid and powder):
- Liquid form: As, Pb, and Hg each <0.005 mg/kg for 4 of 5 batches; <0.01 mg/kg for the 5th batch. Cd: only 1 batch analysed, <0.01 mg/kg.
- Powder form: As = 0.005, 0.006, 0.007, 0.007, <0.01 mg/kg across 5 batches. Pb and Hg: <0.005 mg/kg for 4 batches, <0.01 mg/kg for the 5th. Cd: only 1 batch, <0.01 mg/kg.
Panel’s recommended practical limits (based on data + modulation factor of 5 for headroom): 0.05 mg/kg for each of As, Pb, Cd, Hg — vs. applicant’s proposed limits of 1.0/0.5/0.5/0.5 mg/kg. Panel noted the applicant’s proposed limits are 50–100× higher than the actual analytical data.
EFSA health-based guidance values (reference points used in risk assessment):
- As: BMDL01 range 0.3–8 µg/kg bw/day (lung, skin, bladder cancers; skin lesions from human data)
- Pb: BMDL01 = 0.5 µg/kg bw/day (1-point IQ reduction in children)
- Cd: TWI = 2.5 µg/kg bw/week (tubular damage biomarker)
- Hg (inorganic): TWI = 4 µg/kg bw/week (kidney weight changes in rats, BMDL10 with UF 100)
Dietary exposure to buffered vinegar (refined estimate, Table 5, mg/kg bw/day as acetic acid equivalents):
- Mean: 8.9 (infants) to 280.3 (children) mg/kg bw/day
- p95: 27.9 (infants) to 1,078.2 (toddlers) mg/kg bw/day
Risk assessment for toxic elements at applicant’s proposed specification limits (Table 8): At 1 mg/kg As in the additive and highest mean exposure (children, 280.3 mg/kg bw/day AAEs = 1,583.6 mg/kg additive in liquid form at 17.7% AAEs): MOE for As = 0.189–5.1 (insufficient, safety concern); MOE for Pb = 0.63 (insufficient); Cd exposure = 221.7% of TWI; Hg exposure = 138.6% of TWI. All four elements raise concern at proposed specification limits.
Risk assessment at data-derived limits (0.05 mg/kg per element, Table 9): MOE for As = 3.789–101.0 (still insufficient at lower end of range); MOE for Pb = 6.31; Cd = 22.2% of TWI; Hg = 13.9% of TWI. Safety concern remains for As even at data-derived limits.
Main food categories contributing to buffered vinegar exposure: soups and broth (FC 12.5, up to 63.5% of mean exposure) and bread and rolls (FC 07.1, up to 55.3%).
Note: EFSA’s risk management conclusion is that the choice of maximum limits for toxic elements in specifications is in the remit of risk management (not the Panel’s role). The Panel’s safety conclusion is for acetic acid/acetate exposure — not for heavy metal impurities at the proposed specification limits.
Methods (brief)
This is an EFSA scientific opinion (regulatory risk assessment), not a primary measurement study. Heavy metal data from applicant (Kemin Industries BV and Purac Biochem BV) analysed by ICP-MS per USP 233 method on 5 independent batches each of liquid and powder forms. Exposure assessment: EFSA Comprehensive European Food Consumption Database (July 2021 version), FAIM tool v2.1, SAS Enterprise Guide v8.2.5, 22 EU countries, 6 population groups (infants through elderly). Food category linkage via FoodEx2 classification. Proposed use levels cover 24 food categories, maximum/typical 3,000–30,000 mg/kg expressed as acetic acid equivalents.
Implications
Certification: This opinion establishes that buffered vinegar used as a food additive in EU can carry As, Pb, Cd, and Hg impurities at levels that, if present at applicant’s proposed limits, would create safety concerns particularly for As and Pb. The actual measured concentrations in production batches are all <0.01 mg/kg — far below both the proposed limits and the Panel’s recommended limits. For HMT&C product certification, any product using buffered vinegar as an additive should verify toxic element content in the buffered vinegar ingredient itself.
Regulations: Cross-link to eu-1333-2008-food-additives and efsa-contam-lead, efsa-contam-arsenic, efsa-contam-cadmium, efsa-contam-mercury.
Courses: Illustrates EFSA’s systematic approach to heavy metal impurity risk assessment in food additives; demonstrates margin-of-exposure (MOE) and TWI frameworks in application.
App: Buffered vinegar as a food additive ingredient carries heavy metals at very low concentrations in practice (<0.01 mg/kg each for As, Pb, Hg, Cd), but regulatory headroom in specifications is much wider. This is a regulatory and QC consideration, not a typical-contamination finding.