Heavy Metals in Milk and Dairy Products: Safety and Analysis
M. Renata S. Souto, Adriana M. Pimenta, Rita I. L. Catarino, M. Fernanda C. Leal, Eugénia T. R. Simões
Abstract
Milk and dairy products play a key role in the human diet but may also be vehicles for toxic contaminants, particularly heavy metals and metalloids (HMs), such as lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As). This integrative review examines peer-reviewed studies published between 2015 and 2025 to examine sources, occurrence, and health risks associated with HM contamination in milk and dairy products. Key sources include industrial emissions, agricultural runoff, contaminated feed and water, and inadequate packaging. This review highlights regulatory inconsistencies, limited surveillance, and underuse of metal speciation analysis, which hinder accurate toxicity assessment. Advances in trace-level HM detection systems are discussed in terms of sensitivity, accessibility, and feasibility. Studies from diverse geographic regions frequently report high levels of Pb and Cd in samples originating from industrialized areas in low- and middle-income countries. Health risk indicators, such as target hazard quotients (THQs) and margins of exposure (MOEs), often exceed safety thresholds, particularly in children, indicating significant public health risks, especially with prolonged exposure. These findings underscore the urgent need for systematic contaminant monitoring, harmonized regulations, source-focused mitigation policies, and investment in rapid, cost-effective testing technologies to safeguard milk and dairy product safety worldwide.