Ibrahim et al. 2025 — Multi-metal occurrence in flavored dairy products, Egypt
This study measured 15 trace and toxic elements (Al, Pb, Hg, Cd, As, Sb, Zn, Fe, Cu, B, Se, Ni, Co, Cr, Mn) in 180 samples of flavored dairy products from Egyptian retail markets using ICP-MS/MS, with health risk assessment for children aged 1-5 years. Products included UHT milk, pasteurized milk, milk powder, yogurt, drinking yogurt, and ice cream across chocolate, strawberry, peach, and vanilla flavors. Mercury and cadmium were below LOD in all samples. Pb exceeded the EU regulatory limit (0.02 mg/kg) in strawberry milk powder and pasteurized milk; estimated daily intakes of Pb and Al exceeded tolerable daily intakes for toddlers consuming strawberry drinking yogurt twice daily, with non-carcinogenic hazard quotients of 1.870-3.740 and carcinogenic risk for As and Pb of 8.40×10⁻⁴ to 1.68×10⁻³.
Key numbers
Reported as mean ± SD in mg/kg (wet weight). LOD for Cd = 0.032 ppb; LOQ for Cd = 0.106 ppb; LOD for Hg = 0.072 ppb; LOQ for Hg = 0.237 ppb.
Selected toxic element concentrations by product (Table 1):
| Product | Pb (mg/kg) | tAs (mg/kg) | Al (mg/kg) | Sb (mg/kg) | Cd | Hg |
|---|---|---|---|---|---|---|
| C-UHT milk | 0.027±0.004 | ND | 1.345±0.468 | ND | <LOD | <LOD |
| S-UHT milk | 0.073±0.058 | ND | 0.847±0.341 | ND | <LOD | <LOD |
| C-pasteurized milk | 0.028±0.004 | 0.0016±0.001 | 1.013±0.487 | ND | <LOD | <LOD |
| S-pasteurized milk | 0.004±0.003 | ND | 0.833±0.409 | ND | <LOD | <LOD |
| C-milk powder | 0.075±0.014 | 0.009±0.005 | 4.785±1.590 | ND | <LOD | <LOD |
| S-milk powder | 0.005±0.001 | ND | 2.591±0.568 | ND | <LOD | <LOD |
| S-yogurt | 0.090±0.036 | 0.037±0.031 | 2.926±0.771 | ND | <LOD | <LOD |
| P-yogurt | 0.059±0.026 | 0.020±0.003 | 1.985±0.859 | ND | <LOD | <LOD |
| S-drinking yogurt | 0.104±0.052 | 0.0034±0.0025 | 3.736±1.323 | ND | <LOD | <LOD |
| P-drinking yogurt | 0.025±0.012 | ND | 4.028±0.979 | 0.021±0.025 | <LOD | <LOD |
| C-ice cream | 0.051±0.042 | 0.005±0.004 | 1.790±0.777 | ND | <LOD | <LOD |
| V-ice cream | 0.068±0.039 | ND | 0.914±0.307 | 0.0017±0.0019 | <LOD | <LOD |
C = chocolate, S = strawberry, P = peach, V = vanilla; ND = not detected.
Ni detected only in S-yogurt: 1.591±1.746 mg/kg (53.33% prevalence). Cr ranged up to 1.279±0.52 mg/kg in C-milk powder.
EU regulatory limit for Pb in milk and dairy: 0.02 mg/kg; exceeded in S-UHT milk (0.073), C-milk powder (0.075), and S-drinking yogurt (0.104).
Detection rates: Pb detected in 86.67% of products overall (not detected in peach yogurt only). tAs detected in 60-100% depending on product. Al detected at 100% prevalence across all products.
Health risk (toddlers, twice-daily consuming S-drinking yogurt): THQ for Pb = 1.870-3.740; THQ for Al exceeded TDI; total carcinogenic risk (Pb + As + Ni) = 8.40×10⁻⁴ to 1.68×10⁻³ (exceeds acceptable upper bound of 10⁻⁴).
Methods (brief)
Analytical method: ICP-MS/MS (Agilent 8800 Triple Quad) following Agilent 5991-2802EN protocol; analysis at ISO-accredited mineral lab (ISO/IEC 17025), Regional Center for Food and Feed (RCFF), Giza, Egypt. Sample prep: microwave digestion with 6 mL HNO3 (69%) + 1 mL HCl (37%); 200 °C hold; 0.2 mg/L gold added for Hg stabilization. Quality control: 5-point calibration with R² ≥ 0.99 for all analytes; internal standard recovery 90-110%; RSD 1-5%. Basis: wet weight (products analyzed as-purchased; digested without prior drying). Species: total arsenic (no speciation performed; tAs only); total Hg below LOD in all samples; total Cd below LOD in all samples.
Note on arsenic speciation: the paper reports total arsenic. In dairy matrices, organic arsenicals (especially arsenobetaine from animal feed) may contribute to tAs; inorganic arsenic fraction is not reported. tAs values must not be interpreted as iAs.
Implications
Certification: Lead exceedances above the EU 0.02 mg/kg limit in flavored milk products from Egypt, especially strawberry flavors, confirm that dairy product formulation (added flavorings, colorants, additives) introduces a meaningful Pb contamination pathway beyond the base milk itself. Chocolate milk powder showed the highest Al concentrations (4.785 mg/kg), consistent with cocoa-derived Al inputs. Cd and Hg were below LOD, consistent with dairy-matrix Cd and Hg dilution relative to feed-intake pathways.
Courses: Demonstrates that flavor additives (chocolate, strawberry) substantially alter the toxic element profile of dairy products relative to plain milk; illustrates risk layering across product sub-type and consumer age group.
App: Contributes occurrence data for Pb, tAs, Al, Ni, Cr, Sb in flavored milk, milk powder, yogurt, and ice cream. Note this is an Egyptian market survey; regulatory context is EU limits for Pb; results are broadly representative of lower-regulation markets.