Bora et al. 2022 — Heavy metals in Romanian fruits and vegetables, with vinegar washing reduction
This study quantified arsenic, cadmium, lead, and zinc in 80 fruit and vegetable samples from Galati County, Romania using ICP-MS, comparing contamination between market-sourced and amateur-farm-sourced produce, and then testing the ability of vinegar washing (5% and 10% acetic acid) to reduce heavy metal concentrations. Market-sourced samples had higher metal levels than amateur-farm samples across all metals, with differences up to 35% (As), 68% (Cd), 67% (Pb), and 3% (Zn). Vinegar washing at 10% acetic acid reduced As and Zn by up to 8% and Cd by up to 20%, while Pb showed no reduction from vinegar washing. The paper’s relevance for the vinegar ingredient entry is primarily as evidence that acetic acid washing is a recognized but limited mitigation intervention for produce metals, and that vinegar itself functions as a processing reagent rather than a meaningful metal contamination source in this context.
Key numbers
All values in µg/kg fresh weight (FW) unless noted. ICP-MS analytical LODs: As 0.711 µg/L (LoQ used as reporting threshold), Cd and Pb values not specified but <µg/kg range.
Arsenic (fruiting vegetables, n subset): range below LoQ to 388.86 µg/kg FW; mean fruiting vegetables 182.97 µg/kg FW. Tomato max: 381.56 µg/kg FW. Yellow cherry tomato: 254.53 µg/kg FW. Long cucumber: 249.13 µg/kg FW. White beans: 146.29 µg/kg FW. Garlic: 180.70 µg/kg FW. Fruits mean: 33.13 µg/kg FW. Leafy vegetables mean: 2.69 µg/kg FW. Root vegetables: <LoQ. Market samples up to 35% higher As than amateur farm samples (means: market 85.08, amateur 63.09 µg/kg FW).
Cadmium: Market-sourced samples up to 68% higher Cd than amateur-farm samples. Specific values by commodity in Table 1 (not fully extracted; large table with n=80 observations by produce type and source).
Lead (fruiting vegetables subset from Table 1 partial): Tomato: Pb market 66.81 ± 12.38, amateur 73.34 ± 15.72 µg/kg FW. Several other fruiting vegetables at 18–112 µg/kg FW range. Market samples up to 67% higher Pb than amateur-farm samples.
Zinc: Range in fruiting vegetables 1358–4113 µg/kg FW (Table 1 values). Market vs amateur difference ~3%.
Vinegar washing efficacy (% reduction from baseline):
- As: up to 8% reduction with 10% acetic acid wash
- Zn: up to 8% reduction with 10% acetic acid wash
- Cd: up to 20% reduction with 10% acetic acid wash
- Pb: no reduction detected from vinegar washing (5% or 10%)
Regulatory comparison: Romanian MAL and EU Commission Regulation EC No. 1881/2006 apply. As values below Romanian MAL (0.5 mg/kg) but many samples exceed Codex Alimentarius recommended limit (0.1 mg/kg) for As in fruits/vegetables.
Methods (brief)
ICP-MS (iCAP Q, Thermo Fisher Scientific) with ASX-520 autosampler; isotopes monitored: 65Zn, 75As, 111Cd, 208Pb. Ge, Tb, Rh, Sc internal standards at 50 µg/L. Microwave digestion (Milestone START D): 0.5 g dry sample + 7 mL 65% HNO3 + 2 mL H2O2. Samples dried at 105°C (72–92 h) and ground through 2 mm sieve before digestion; concentrations reported on dry-weight basis then converted to fresh-weight. Global recovery: 97–102% for all elements. RSD <5% for triplicates. CRM used for accuracy verification. Vinegar washing: glass bowl immersion in 5% or 10% acetic acid vinegar for 5–10 min at 30°C, followed by same ICP-MS analysis protocol.
Implications
Certification: This paper does not report metal concentrations in vinegar itself. Its relevance is twofold: (1) it quantifies heavy metals in common fruit and vegetable commodities from Romania (useful for ingredient pages for tomatoes, cucumber, leafy vegetables, garlic, root vegetables); (2) it provides empirical evidence on vinegar washing as a mitigation intervention for produce metals. For the vinegar page, vinegar functions as a mitigation reagent here, not as a contaminated ingredient. The 20% Cd reduction achievable with vinegar wash is modest; Pb is unaffected by vinegar washing.
Courses: Demonstrates that acetic acid washing has a measurable but limited effect on produce metal contamination; Cd is somewhat mobilizable (up to 20%), while Pb is not. The origin-of-produce effect (market vs. amateur farm) is a significant finding: market produce had substantially higher Cd (up to 68%) and Pb (up to 67%) than amateur farm produce in this Romanian dataset, consistent with soil contamination in commercial growing areas.
App: Primary value is for fruit and vegetable ingredient contamination profiles, not for the vinegar ingredient itself. Tomatoes, cucumbers, leafy vegetables, and garlic show detectable As in this Romanian dataset.