Concentrations of Heavy Metals in Processed Baby Foods and Infant Formulas Worldwide: A Scoping Review

Summary

This scoping review synthesizes global evidence for Pb, Cd, arsenic, and mercury concentrations in processed baby foods and infant formulas. It is useful for Category 1 as an evidence map and prioritization source, but primary-study values should be preferred for final p-value aggregation where available.

Key numbers

The review included 75 studies covering 580 baby foods and 251 infant formulas.
Pb, Cd, and As were detected in more than 60 percent of baby foods.
For baby foods, the highest Pb median was reported in rice mixes and fish mixes, 0.008 mg/kg each.
For baby foods, the highest Cd median was reported in cereals, 0.013 mg/kg, and mixed foods, 0.008 mg/kg.
For baby foods, the highest As median was reported in mixed fish, 0.165 mg/kg, and rice mixes, 0.048 mg/kg.
For infant formulas, Pb, Cd, and As were detected in more than 60 percent of items.
For infant formulas, the highest Pb median concentrations were in stages 1 and 2, 0.015 mg/kg each.
For infant formulas, without-stage formulas had the highest As median, 0.052 mg/kg.
Across baby food items, the review reports detection in 69 percent for Pb, 72 percent for Cd, 73 percent for As, and 34 percent for Hg.
Across infant formula items, the review reports detection in 74 percent for Pb, 61 percent for Cd, 63 percent for As, and 42 percent for Hg.
By primary protein source, Pb was detected in 73 percent of cow-based formula items and 84 percent of soy-based formula items; Cd was detected in 44 percent of cow-based formula items and 91 percent of soy-based formula items.

Review-level concentration rows

These are secondary-review medians and exceedance summaries. They are useful for prioritization and gap analysis, but should not be pooled with primary-study product rows for HMTc p90/p100 calculations.

Evidence item	Product fit	Metal	Review statistic	Approximate ppb equivalent	Use note
Rice/rice-mix baby foods	Baby Cereals / Grain Products, Dry (Rice-Based), Mixed Meals, Rice-Containing, Teething & Snacks (Rice-Based)	Pb	median 0.008 mg/kg; 31% of detected items exceeded the Pb ML used by the authors	8 ppb	Broad rice/rice-mix group, not row-specific.
Rice/rice-mix baby foods	Baby Cereals / Grain Products, Dry (Rice-Based), Mixed Meals, Rice-Containing, Teething & Snacks (Rice-Based)	As	median 0.048 mg/kg; 30% of detected items exceeded the As ML used by the authors	48 ppb	Review reports As; speciation varies across included studies.
Fish/fish-mix baby foods	Fish-Containing Baby Foods	As	median 0.165 mg/kg; 89% of detected items exceeded the As ML used by the authors	165 ppb	Broad fish/fish-mix group; arsenic species not resolved.
Fish/fish-mix baby foods	Fish-Containing Baby Foods	Hg	median 0.016 mg/kg; Hg detected in all fish/fish-mix determinations in the review grouping	16 ppb	Mercury species not guaranteed across included studies.
Cereal baby foods	Baby Cereals / Grain Products, Dry (Non-Rice), Baby Cereals / Grain Products, Dry (Rice-Based)	Cd	median 0.013 mg/kg; 17% of detected cereal items exceeded the Cd ML used by the authors	13 ppb	Broad cereal group; rice/non-rice split not resolved.
Mixed foods excluding meat/fish/rice	Mixed Meals, Non-Rice	Cd	median 0.008 mg/kg; 19% of detected mixed-food items exceeded the Cd ML used by the authors	8 ppb	Broad non-rice mixed-food context, not a product-specific distribution.
Roots and tubers	Root-Vegetable Purees	Pb	detection in 97% of evaluated roots/tubers; median 0.007 mg/kg	7 ppb	Broad roots/tubers group; not puree-specific.
Infant formulas by stage	Infant Formula, Powder (Non-Soy), Infant Formula, Powder (Soy-Based), Infant Formula, RTF Liquid (Non-Soy), Infant Formula, RTF Liquid (Soy-Based)	Pb	stage 1 and stage 2 medians each 0.015 mg/kg; 60% of detected stage 1 and 72% of detected stage 2 items exceeded the Pb ML used by the authors	15 ppb	Stage-level formula context; not powder/RTF-specific.
Infant formulas by protein source	Infant Formula, Powder (Non-Soy), Infant Formula, RTF Liquid (Non-Soy)	Pb	cow-based formula median 0.005 mg/kg; 34% of detected cow-based items exceeded the Pb ML used by the authors	5 ppb	Protein-source context; no format split.
Infant formulas by protein source	Infant Formula, Powder (Soy-Based), Infant Formula, RTF Liquid (Soy-Based)	Cd	Cd detected in 91% of soy-based formula determinations; soy-based median 0.001 mg/kg	1 ppb	Protein-source context; no format split.
Infant formulas without stage	formula bridge context	As	median 0.052 mg/kg; 71% of detected without-stage formula items exceeded the As ML used by the authors	52 ppb	Useful retrieval target for underlying primary sources, not direct row math.

Health-risk review findings

The review identified 41 studies that conducted infant health-risk assessments; 15 reported risks associated with intake of baby foods or infant formulas. Risk findings clustered around rice products for infants 6 months and older, especially for As and Cd, and around stage 1 and 2 formulas for infants under 12 months, especially for As, Pb, and Cd.

Methods (brief)

The review followed JBI scoping-review methods and PRISMA-ScR reporting. Baby foods were classified into seven primary-ingredient groups, and infant formulas were classified by stage and specialty status.

Limitations

This is a secondary synthesis under a CC BY-NC-ND license. It is useful for coverage mapping and identifying primary studies, but the standards pipeline should avoid double-counting review medians alongside the primary datasets they summarize. Several classifications are broad, including rice/rice-mix, fish/fish-mix, cereals, stage formulas, and primary protein source; these categories do not map one-to-one to the locked HMTc rows.

Implications

Certification: Useful as a global evidence map and citation trail for Category 1, not as a substitute for primary concentration rows.

Courses: Useful overview of why rice, fish, cereals, mixed foods, and formula require different treatment.

App: Useful for retrieval ranking and identifying missing primary-study targets.

Microbiome: No direct microbiome endpoint.

Update history

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