Altalib et al. 2025 — Heavy metals in imported frozen meat, Tripoli markets
This cross-sectional study measured lead (Pb), cadmium (Cd), chromium (Cr), and copper (Cu) in 30 imported frozen meat samples collected from retail markets in Tripoli, Libya. Samples included chicken (50% of total), beef (27%), and lamb (23%), sourced from Brazil, USA, Jordan, Spain, and Australia. Analysis was by Atomic Absorption Spectrophotometry (AAS) following acid digestion. All samples complied with Libyan and international safety limits for Cd, Cr, and Cu; one sample (3.3%) exceeded the Libyan Pb limit of 0.10 mg/kg. The study provides a baseline Pb, Cd, and Cr dataset for imported commercial meat in a North African market context.
Key numbers
All values reported as mg/kg wet weight. Libyan standard limits: Pb 0.10 mg/kg, Cd 0.05 mg/kg, Cr 1.00 mg/kg.
Lead (Pb):
- Mean: 0.0145 mg/kg (14.5 µg/kg / 14.5 ppb)
- SD: 0.0480 mg/kg
- Minimum: 0.0020 mg/kg (2.0 ppb)
- Maximum: 0.2570 mg/kg (257 ppb) — one sample exceeded Libyan limit of 100 ppb
- 29 of 30 samples (96.7%) below 0.10 mg/kg; 1 sample (3.3%) above
- By meat type: chicken highest mean (0.02667 mg/kg), beef (0.0025 mg/kg), lamb (0.00212 mg/kg)
- By origin: Jordan highest mean (0.07446 mg/kg); others ranged 0.00200–0.00289 mg/kg
Cadmium (Cd):
- Mean: 0.0017 mg/kg (1.7 ppb)
- SD: 0.0003 mg/kg
- Minimum: 0.0010 mg/kg (1.0 ppb)
- Maximum: 0.0023 mg/kg (2.3 ppb)
- 100% of samples below Libyan limit of 0.05 mg/kg
- By meat type: chicken highest mean (0.00184 mg/kg), beef (0.00176 mg/kg), lamb (0.00151 mg/kg)
Chromium (Cr; total chromium — speciation not performed):
- Mean: 0.0244 mg/kg (24.4 ppb)
- SD: 0.0204 mg/kg
- Minimum: 0.0090 mg/kg (9.0 ppb)
- Maximum: 0.0830 mg/kg (83.0 ppb)
- 100% of samples below Libyan limit of 1.00 mg/kg
- Authors explicitly note that AAS cannot differentiate Cr(III) from Cr(VI); advanced speciation methods recommended
Copper (Cu; not regulated under Libyan standards):
- Mean: 0.5142 mg/kg; range: 0.1187–0.9233 mg/kg
- Highest mean in beef (0.7541 mg/kg); significant variation by meat type (p<0.001)
ANOVA results (one-way, p<0.05 significance threshold):
- Pb by meat type: p=0.217 (NS); Cd by meat type: p=0.297 (NS); Cr by meat type: p=0.535 (NS); Cu by meat type: p=0.000 (significant)
- No significant differences by meat cut or country of origin for any metal (p>0.05 for all)
Methods (brief)
Cross-sectional study; 30 samples collected Feb–May 2025 from Tripoli retail markets. Samples mechanically homogenized; 1.0 g dried sample digested with concentrated HNO₃ and perchloric acid or H₂O₂; diluted to 50 mL. Flame AAS (unspecified instrument). Total chromium only; Cr(VI) speciation not performed. Standard solutions prepared from 1000 mg/L certified stock solutions (Pb, Cd, Cu, Cr). Statistical analysis: SPSS v26, one-way ANOVA. Sample size (n=30) is small; no LOQ/LOD values reported in the text; the single Pb exceedance sample is an outlier substantially above the distribution mean.
Implications
Certification: The 257 ppb Pb maximum in one chicken sample and the overall chicken-highest Pb mean are consistent with findings in other middle-income market surveys. The Cd range (1.0–2.3 ppb) is well below EU/Codex limits for muscle meat. The Cr data are total Cr only; the authors correctly flag that Cr(VI) determination requires speciation methods — this is the same wiki rule (total Cr ≠ Cr(VI)) documented at chromium-hexavalent. The Jordan-origin Pb spike (mean 74.5 ppb vs Brazil/USA/Spain/Australia at 2–3 ppb) is flagged but is not statistically significant at p=0.795, likely due to the very small per-country subsample sizes.
Courses: Useful case for illustrating the difference between regulatory compliance at the population level and individual outlier risk. The mean Pb is well below limits, but a single sample at 257 ppb (2.57× the Libyan limit) illustrates why lot-level testing matters.
App: Beef, chicken, and lamb muscle: Pb in the low double-digit ppb range for the great majority of commercial imports; Cd in the 1–2 ppb range. The single outlier at 257 ppb is not representative of the distribution. Total Cr 9–83 ppb range is uninformative for Cr(VI) risk without speciation.