Heavy metal levels in camel milk and health risk assessment: A global systematic review

Abstract

Introduction: This systematic review investigates the potential toxicity of metals and metalloids, including lead (Pb), mercury (Hg), cadmium (Cd), and nickel (Ni), in raw camel milk, with a focus on health risk assessment for human consumption through the calculation of Target Hazard Quotient (THQ) and Carcinogenesis Risk (CR). Methods: From 927 initial articles, we analyzed 20 original articles, comprising 787 samples published between 2000 and 2024. Results: Pb levels ranged from nondetectable to 1.560 mg.kg−1, while Cd levels ranged from 0.0008 to 0.800 mg.kg−1. Egypt and Saudi Arabia reported the highest levels of Pb, Ni, and Cd. Pb concentrations in milk exceeded the Codex Alimentarius recommended limit (0.020 mg.kg−1) in 10 out of 18 studies. Overall, Pb and Cd exposure through milk consumption appeared safe for humans, although THQ values exceeded 1 in two Pb studies out of 18 and in one Cd study out of 16. Conclusion: This study contributes to establishing an international database on toxic metal levels in camel milk, informing strategies for managing metal-related risks in milk consumption.

Keywords

• Camel milk
• Heavy metals
• Risk assessment
• Systematic review