Acosta et al. 1993 — Cd, Pb, and Ni in different types of vinegar
This study measured cadmium, lead, and nickel in 52 commercial bottled vinegars (wine, apple, alcohol, and malt types) purchased from supermarkets in the Canary Islands, Spain, using flame atomic absorption spectrophotometry (FAAS) after ashing at 500°C. Lead concentrations differed significantly by vinegar type, with apple vinegar lowest and malt vinegar highest; cadmium showed no significant inter-type difference and was non-detectable in the majority of samples; nickel showed no significant inter-type difference. Only 3 samples (6%) exceeded the Spanish legal limit of 1 ppm total for Pb + Hg + As. The data are among the earliest systematic occurrence datasets for cadmium, lead, and nickel across multiple commercial vinegar types.
Key numbers
All results in ppm (mg/kg); detection limits: Cd 0.012 ppm, Pb 0.035 ppm, Ni 0.047 ppm.
Cadmium (overall, n=52):
- Mean: 0.028 ppm; SD: 0.042; max: 0.245 ppm; min: 0.012 ppm (or n.d., 33% non-detectable)
- Wine vinegar (n=26): mean 0.035, max 0.245; 27% n.d.
- Apple vinegar (n=10): mean 0.022, max 0.037; 20% n.d.
- Alcohol vinegar (n=10): mean 0.014, max 0.017; 60% n.d.
- Malt vinegar (n=6): mean 0.020, max 0.025; 33% n.d.
- 94% of samples below 0.04 ppm Cd; no significant inter-type difference (p<0.1)
Lead (overall, n=52):
- Mean: 0.60 ppm; SD: 0.22; max: 1.28 ppm; min: 0.35 ppm (19% n.d.)
- Wine vinegar (n=26): mean 0.67, max 1.28; 24% n.d.
- Apple vinegar (n=10): mean 0.44, max 0.55; 40% n.d.
- Alcohol vinegar (n=10): mean 0.52, max 0.76; 10% n.d.
- Malt vinegar (n=6): mean 0.60, max 0.68; 0% n.d.
- Significant inter-type difference (p<0.1); apple vinegar significantly lower than wine (p<0.05) and malt (p<0.001)
- Brand C (wine vinegar, Canary Islands): highest mean Pb, no non-detects
Nickel (overall, n=52):
- Mean: 0.102 ppm; SD: 0.042; max: 0.206 ppm; min: 0.047 ppm (15% n.d.)
- No significant inter-type differences (p<0.1); wine vinegar D brand significantly higher in Ni (p<0.05)
Note: units are ppm = mg/kg = mg/L (for aqueous liquid matrices). To convert to ppb (µg/kg): multiply by 1000. So mean Pb = 600 µg/kg, max = 1280 µg/kg across all types; mean Cd = 28 µg/kg; mean Ni = 102 µg/kg.
Regulatory context: Spanish legal limit 1 ppm total for Pb + Hg + As. Only 3 of 52 samples (6%) exceeded this for lead alone. FAO/WHO Codex draft (1982) proposed: Pb 1 mg/kg, Cu 10 mg/kg, Zn 10 mg/kg, Fe 30 mg/kg.
Recovery: Cd 95.0 ± 4.7%, Pb 92.8 ± 7.8%, Ni 100.7 ± 4.8%. Noted ~5–7% losses for Cd and Pb during ashing (volatilization); recoveries considered acceptable.
Methods (brief)
Flame atomic absorption spectrophotometry (FAAS): Varian Spectr AA-10 Plus, air/acetylene flame. Wavelengths: 228.8 nm (Cd), 217.0 nm (Pb), 232.0 nm (Ni). Sample preparation: 50 mL vinegar evaporated to dryness, then ashed in furnace at 500 ± 25°C (ramped at 25°C/30 min); white ash dissolved in 1:1 HCl. Six measurements per sample per metal. Statistical analysis: ANOVA with Student-Newman-Keuls test. Note: ashing method is a limitation vs. acid digestion; the ~7% Pb loss is acknowledged by authors.
Implications
Certification: Lead is the metal of primary concern in vinegar across types; mean 600 µg/kg with maximum 1280 µg/kg. Apple cider vinegar shows the lowest lead burden (mean 440 µg/kg). Cadmium in vinegar is generally very low (94% of samples <40 µg/kg, most n.d.). Nickel is detectable in most samples at low levels (mean ~100 µg/kg).
Courses: Early (1993) baseline dataset. Methodology is dated (ashing with known Pb volatilization losses vs. modern acid digestion); values may be slightly underestimated for Pb and Cd. Useful for historical context but should be interpreted alongside more recent acid-digestion data (e.g., Ndung’u 2004).
App: Pb in wine vinegar at ~600–1280 µg/kg is meaningfully higher than apple cider vinegar (~440 µg/kg). Cd and Ni in vinegar are very low.