Advances in the Standards & Applied Sciences

Advances in the Standards & Applied Sciences

Seasonal Occurrence and Quantification of Pb, Cd, and Hg in Commercial Pasteurized Milk Brands Distributed in Tehran

Document Type : Original Article

Authors
Ghazaleh Aliakbarzadeh
Somayeh Hasani Ganji
Masoumeh Mahmoudi-Meymand
Food Toxicology Research Group, Food Technology and Agricultural Products Research Center, Standard Research Institute (SRI), P.O. Box 31745-139, Karaj, Iran
10.22034/asas.2026.565884.1091
Abstract
Milk is a major dietary component, particularly for vulnerable population groups, which makes monitoring its contamination by heavy metals essential for public health protection. This study investigated the concentrations of lead (Pb), cadmium (Cd), and mercury (Hg) in 40 samples from 10 commercial pasteurized/sterilized milk brands available in the Iranian market, collected across the four seasons in 2023. Heavy metals were quantified using validated standard methods, with a certified reference material (CRM) and reagent blanks analyzed to verify analytical accuracy and precision.
Of the 40 samples, Pb was undetectable in 3 (7.5%), below the maximum permissible limit (MPL) of 0.02 mg/kg in 36 (90%), and exceeded the MPL in only one sample (2.5%). Seasonal trends revealed higher average Pb levels in spring and autumn relative to summer and winter. Cd, concentrations were undetectable in 26 samples (65%) and measurable but below the MPL in 14 (35%). Hg was undetectable in 18 samples (45%) and quantifiable, albeit at low levels, in 22 (55%). Overall, Pb was the predominant contaminant, while Cd and Hg occurred less frequently and at negligible levels.
Keywords
pasteurized milk
heavy metals
matrix digestion
atomic absorption spectrometry
Subjects
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Advances in the Standards & Applied Sciences
Volume 3, Issue 4
Summer 2025
Pages 143-149