Balbo and Wozniak 2022 — Chemical contaminants including heavy metals in rye-wheat bread, Poland
This EFSA EU-FORA technical report measured acrylamide, mycotoxins (DON and related compounds), and six heavy metals (Al, As, Cd, Cr, Pb, Ni) in 51 loaves of rye-wheat bread (refined flour) randomly purchased in Warsaw, Poland. Heavy metal occurrence was measured by ICP-MS per European standard EN 15763:2009. All heavy metal concentrations were below EU maximum levels for the applicable matrices. However, estimated dietary exposures for aluminium, lead, and nickel raised public health concerns across some population groups, particularly toddlers and children, when combined with EFSA consumption data.
Key numbers
Heavy metal concentrations in rye-wheat bread, n=51 loaves (µg/kg fresh weight, expressed as geometric mean upper bound):
| Analyte | Mean (µg/kg) | Median (µg/kg) | SD (µg/kg) | Geometric mean UB (mg/kg) |
|---|---|---|---|---|
| Aluminium | 4054 | 3919 | 1251 | 4.11 |
| Arsenic | 5.62 | 5.10 | 2.39 | 0.01 |
| Cadmium | 13.93 | 13.21 | 3.60 | 0.01 |
| Chromium | 134.61 | 106.17 | 84.5 | 0.13 |
| Lead | 82.39 | 72.50 | 54.33 | 0.08 |
| Nickel | 260.82 | 234.39 | 101.97 | 0.26 |
EU maximum levels applicable to rye-wheat bread: Cd 0.05 mg/kg (rye and barley), Pb 0.2 mg/kg (cereals and pulses). Geometric mean UB for Pb (0.08 mg/kg) was below the ML but notably higher than the 0.044 mg/kg mean UB reported in the EFSA 2010 lead opinion for cereals generally.
Dietary exposure findings: Al exceeded EFSA’s TWI of 1 mg/kg bw per week for all population groups; Pb MOEs were below the safe level across all population groups; Cd exceeded TWI for toddlers and other children; Ni TDI exceeded for toddlers. Arsenic estimated dietary exposures for toddlers and other children were within the range of BMDL01 values for lung and bladder cancer.
Methods (brief)
ICP-MS after pressure digestion per European standard EN 15763:2009. Samples lyophilized before analysis. Dietary exposure estimated by multiplying 95th percentile consumption data (from EFSA Comprehensive European Food Consumption Database, IZZ FAO 2000 24-h recall data for Poland) by geometric mean UB occurrence concentration. Data assumed log-normal distribution.
Implications
Certification: rye-wheat bread shows measurable Al (mean ~4 mg/kg FW), Pb (mean ~82 µg/kg FW), Cr (mean ~135 µg/kg FW), and Ni (mean ~261 µg/kg FW). Pb at mean 82 µg/kg is approximately 2x the European cereal average. These levels combined with typical Polish bread consumption raise dietary exposure concerns particularly for toddlers and children.
Courses: EFSA EU-FORA report demonstrating multi-contaminant assessment framework including heavy metals, mycotoxins, and process contaminants simultaneously in a staple food.
App: rye and wheat bread ingredients carry measurable Pb, Ni, Al, and Cr. Geographic sourcing (Poland) may influence levels.