Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. 
Clinical Pharmacist and Master’s student in Clinical Pharmacy with research interests in pharmacovigilance, behavioral interventions in mental health, and AI applications in clinical decision support. Experience includes digital health research with Bloomsbury Health (London) and pharmacovigilance practice in patient support programs. Published work covers drug awareness among healthcare providers, postpartum depression management, and patient safety reporting. What was reviewed?
This review synthesizes evidence on heavy metal reduction in food processing, assessing how conventional and emerging unit operations mitigate cadmium, lead, arsenic, mercury, and related elements without unacceptable quality losses. Drawing on studies across vegetables, grains, seaweeds, seafood, oils, dairy, and processed foods, it maps mechanisms of chelation, leaching, adsorption, electroporation, redox conversion, and phase partitioning against measurable removal percentages. The graphical abstract (p.2) distinguishes conventional pre-treatments from novel thermal and nonthermal technologies and emphasizes operational constraints such as energy, scalability, and sustainability. Table summaries detail detection methods (AAS, ICP-OES/MS) and reported foodborne concentrations, enabling alignment of heavy metal reduction in food processing with HTMC decision rules.
Who was reviewed?
Evidence spans laboratory and pilot-scale studies using plant matrices (leafy greens, roots, seaweeds), cereals (wheat, rice, maize), animal products (fish, crustaceans, milk), and processed foods (oils, tea, jams). Processing domains include washing/soaking, blanching/boiling, pressing/refining, microwave/IR/RF/ohmic heating, high-pressure processing, cold plasma, pulsed electric fields, ultrasound, supercritical CO₂ extraction, irradiation, membrane filtration, and biological controls (fermentation, probiotics). The tables on pp.7–10 collate pre-treatment and cooking effects, while later sections catalogue nonthermal interventions and biosorption routes, providing cross-commodity coverage relevant to HTMC certified categories.
Most important findings
| Critical point | Details for HTMC |
|---|---|
| Pre-rinses and acids can be highly effective | Citric-acid washing of Ulva reduced Cd by up to 96.12%; color loss was noted, implying sensory trade-offs for specification setting. |
| Household washing/soaking matters | Citric-acid washing of Ulva reduced Cd by up to 96.12%; color loss was noted, implying sensory trade-offs for specification setting. |
| Blanching targets outer-bound metals | Water spinach blanching yielded 48–84% Ni reduction; broader decreases across Cd/Cr/Cu/Ni/Pb/Zn were reported. |
| Cooking can reduce the total but raise the bioaccessibility | Pressure-cooked wheat dropped Cd 49.37%, As 43.14%, Pb 51.79%, yet Cd bioaccessibility rose, cautioning against relying on totals alone. |
| Industrial refining can both help and harm | Oil refining lowered Pb and Cd, but deodorization increased Cu/Cr/Ni from equipment—set migration controls in GMP. |
| Microwave/IR effects are condition-specific | Microwave blanching cut As in Lentinus edodes by 33–43%; mid-IR spray on cocoa cut Ni 66%, As 62%, Pb 44% but impaired flavor at high doses. |
| High-Pressure Processing is promising | As decreased in several sea bass fractions, Pb increased in all extracts in one study—requires matrix-specific validation. |
| PEF can reduce some metals but raise others | As decreased in several sea bass fractions, Pb increased in all extracts in one study—requires matrix-specific validation. |
| Ultrasound aids leaching with shorter times | Cd in crab dropped 22.8% at 35 kHz/50 °C; ultrasound-assisted oil bleaching achieved heavy-metal removal comparable to 30-min industrial runs in 10–12 min. |
| Supercritical CO₂ favors clean oils | Fish oil lost Pb 100%, Cd 97–100%, Hg 85–100%; SC-CO₂ limited seed-to-oil heavy-metal migration vs press extraction. |
| Irradiation shows mixed metal outcomes | Oyster mushroom Zn fell 66.7% at ≥1 kGy; Cd rose in Tetrapleura tetraptera at higher doses—dose control essential. |
| UV depuration can excel in bivalves | Black clams: Pb −96.5%, Cd −40.5%, Cu −34% via UV-assisted recirculating depuration. |
| Biological control is scalable and food-friendly | Fermentation cuts Cd 35–81% in seaweeds/rice; probiotics remove PTEs by biosorption/bioaccumulation. pH and biomass govern efficacy. |
Key implications
For regulators, heavy metal reduction in food processing supports performance-based limits that credit validated process controls. HTMC should specify pretreatment options (acidic washes, blanching) and advanced steps (HPP, UV depuration, SC-CO₂) with quantified removal ranges and bioaccessibility testing. Industry can apply matrix-specific validations and migration controls to avoid equipment-derived metals. Research gaps include condition-dependent reversals (e.g., PEF, irradiation) and sensory/quality impacts. Practically, pair rapid screening (ICP-MS, XRF) with process-control verification plans and require reporting of total and bioaccessible fractions to underpin certification claims.
Citation
Balasubramaniyan Saravanan S, Ukkunda NS, Negi A, Moses JA. Impact of processing techniques on the reduction of heavy metal contamination in foods. Discover Food. 2025;5:123. doi:10.1007/s44187-025-00402-w
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
Cadmium is a persistent heavy metal that accumulates in kidneys and bones. Dietary sources include cereals, cocoa, shellfish and vegetables, while smokers and industrial workers receive higher exposures. Studies link cadmium to kidney dysfunction, bone fractures and cancer.
Lead is a neurotoxic heavy metal with no safe exposure level. It contaminates food, consumer goods and drinking water, causing cognitive deficits, birth defects and cardiovascular disease. HMTC’s rigorous lead testing applies ALARA principles to protect infants and consumers and to prepare brands for tightening regulations.
Arsenic is a naturally occurring metalloid that ranks first on the ATSDR toxic substances list. Inorganic arsenic contaminates water, rice and consumer products, and exposure is linked to cardiovascular disease, cognitive deficits, low birth weight and cancer. HMTC’s stringent certification applies ALARA principles to protect vulnerable populations.
Mercury (Hg) is a neurotoxic heavy metal found in various consumer products and environmental sources, making it a major public health concern. Its regulation is critical to protect vulnerable populations from long-term health effects, such as neurological impairment and cardiovascular disease. The HMTC program ensures that products meet the highest standards for mercury safety.
Heavy metals are high-density elements that accumulate in the body and environment, disrupting biological processes. Lead, cadmium, arsenic, mercury, nickel, tin, aluminum, and chromium are of greatest concern due to persistence, bioaccumulation, and health risks, making them central to the HMTC program’s safety standards.
