Heavy metals in raw milk and Egyptian cheese types

Overview

This Egyptian survey measured seven metals (Pb, Cd, Hg, As, Cu, Fe, Zn) in 100 raw bovine milk samples and 100 cheese samples (three traditional Egyptian varieties: Karish, Domiati, and Ras) collected from Alexandria and Cairo in winter 2021 using flame atomic absorption spectroscopy (AAS). The study found that 46% of raw milk samples exceeded the Egyptian regulatory limit for lead, and 4% exceeded the limit for cadmium. Lead concentrations were highest in Ras cheese, followed by Domiati, Karish, and raw milk in descending order. Mercury and arsenic were detected in subsets of samples. The findings raise food safety concerns given the widespread consumption of these traditional dairy products in Egyptian households.

Key numbers

Raw milk (n=100): Pb mean 0.27 ± 0.01 mg/kg ww (46% of samples exceeded the Egyptian permissible limit of 0.02 mg/kg); Cd mean 0.09 ± 0.01 mg/kg ww (4% exceeded limit); Hg detected in subset; As detected at low levels; Cu mean approximately 0.5 mg/kg; Fe mean approximately 2.1 mg/kg; Zn within normal nutritional range.

Cheese concentrations by type (mg/kg ww, means): Karish — Pb 0.34 ± 0.01, Cd 0.12 ± 0.01, Cu 1.53 ± 0.14; Domiati — Pb 0.55 ± 0.01, Cd 0.18 ± 0.01, Cu 1.69 ± 0.16; Ras — Pb 0.61 ± 0.02, Cd 0.25 ± 0.01, Cu 2.71 ± 0.22. Note: these values align with the gizzard/liver data from Kamouh 2024 (FM_11018418) in suggesting a Pb and Cd contamination pattern in Egyptian animal-derived food commodities tied to environmental exposure of livestock.

Analytical method: Flame AAS. LOD not explicitly stated in the available excerpt. Units: mg/kg wet weight.

Regulatory comparison: Egyptian Organization for Standardization permissible limits cited as Pb 0.02 mg/kg and Cd 0.05 mg/kg for milk. These limits are stricter than Codex ML for Pb in milk (0.02 mg/kg, matching Egypt) and EFSA-assessed values.

Methods (brief)

Sample collection: random selection from Alexandria and Cairo retail/farm sources. Digestion: HNO3/HClO4 mixture. Detection: flame AAS for all seven metals. No speciation performed; reported values are total metal concentrations. Study period: winter 2021.

Limitation: winter-season sampling only; seasonal variation in Pb and Cd in raw milk from Egyptian cattle is not assessed. Alexandria and Cairo are urban/peri-urban markets; rural milk contamination profiles may differ.

Implications

Certification: Documents exceedance rates for Pb (46%) and Cd (4%) in raw Egyptian milk at values well above national MPLs, consistent with a broader pattern of dairy contamination in markets with limited heavy metal regulation enforcement. HMT&C dairy certification should flag Egyptian-origin dairy components.

Courses: Useful for modules on how Pb accumulates in cheese varieties relative to raw milk (concentration effect during ripening and moisture reduction).

App: Egypt-specific range data; contributes to geographic_breakdown entries for Pb and Cd in the dairy ingredient page under a Middle East/North Africa region entry.

Wiki pages updated on ingest

• Lead
• Cadmium
• dairy
• raw-milk
• cheese

Update history

The five most recent substantive edits to this page, classified major (evidence or structure moved), correction (a published value or statement was wrong and has been fixed), or minor (narrative rewritten without changing the underlying evidence). Each description is derived from what the edit did to this page; the linked commit is the authoritative record, routine regeneration passes are excluded, and the full version history lives in git. When DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.