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 comprehensive review paper synthesizes key findings from a USDA-NIFA-sponsored workshop focused on mitigating heavy metal contamination in the food supply. The review critically examines the entire farm-to-fork continuum for five major hazardous elements: arsenic (As), lead (Pb), cadmium (Cd), mercury (Hg), and chromium (Cr). It consolidates current knowledge on their environmental sources, soil biogeochemistry, plant uptake mechanisms, and detoxification pathways. The paper also evaluates multidisciplinary concerns, including food processing risks, detection methods, regulatory standards, and sustainable remediation strategies like phytoremediation, soil amendments, and genetic engineering.
Who was reviewed?
The review integrates and analyzes the collective expertise and discussions of national and international scientists, educators, practitioners, and key stakeholders who participated in the virtual USDA-NIFA workshop held in April 2022. The subject matter experts contributed knowledge across three primary thematic areas: soil biogeochemistry and microbiome interactions; plant uptake and accumulation mechanisms for toxic metals; and multidisciplinary concerns encompassing food processing, detection technologies, and regulatory frameworks. The reviewed body of work encompasses a wide array of prior scientific studies, which investigated the behavior of toxic metals in various agricultural systems, food crops like rice and leafy vegetables, and their subsequent impact on human health, particularly for vulnerable populations such as infants and young children.
Most important findings
| Critical Point | Details |
|---|---|
| Plant Uptake Mechanisms | Toxic metals enter food crops through shared nutrient transporters. Arsenic (AsV) uses phosphate transporters, while arsenite (AsIII) and cadmium (Cd) exploit silicon and iron transporters (e.g., OsNIP2;1/Lsi1, OsNRAMP5), respectively. This complicates efforts to reduce contamination without impacting plant nutrition. |
| Soil Biogeochemistry | Metal bioavailability is highly dependent on soil properties. Lower pH increases cadmium and arsenic mobility, while lead is largely immobile. Soil amendments like biochar, nano-hydroxyapatite, and nanosulfur can effectively immobilize metals and reduce plant uptake. |
| Remediation Strategies | Phytoremediation using hyperaccumulators (e.g., Pteris vittata for arsenic) and genetic engineering (e.g., CRISPR/Cas9 knockout of OsNRAMP5 for cadmium) show promise. Microbial remediation uses specific bacteria to transform metals into less toxic forms, such as reducing Cr(VI) to Cr(III). |
| Food Processing & Detection | Post-harvest handling can alter metal levels; boiling and parboiling can leach out metals, while frying may concentrate them. Advanced detection methods (e.g., ICP-MS, electrochemical sensors) are crucial, but need improvement for on-site, multi-metal detection in complex food matrices. |
| Regulatory Gaps | There is a lack of uniform global standards, especially for baby foods. The U.S. FDA’s “Closer to Zero” initiative is a step forward, but regulatory limits vary widely, and testing finished products, not just raw ingredients, is strongly recommended. |
Key implications
This review has direct primary regulatory impacts, highlighting the urgent need for harmonized, stringent global standards for toxic metals in food, particularly for infant products. For certification requirements, it underscores the necessity of validating supply chains, from soil amendments to processing methods. Industry applications include adopting advanced sensor technologies for real-time monitoring and utilizing soil amendments to mitigate uptake. Significant research gaps persist, including the uncoupling of nutrient and toxic metal uptake pathways and the field-scale efficacy of nano-amendments. Practical recommendations involve promoting government-sponsored soil testing, implementing phased reduction targets, and fostering interdisciplinary collaboration to address this complex food safety challenge effectively.
Citation
Srivastava R, Singh Y, White JC, Dhankher OP. Mitigating toxic metals contamination in foods: Bridging knowledge gaps for addressing food safety.Trends Food Sci Technol. 2024;153. doi:10.1016/j.tifs.2024.104725
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.
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.
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.
