Literature evidence summary
The table below summarizes what the peer-reviewed literature cited on this page reports for heavy-metal concentrations in infant formula. Most rows are from studies covering infant formula broadly without separating RTF from powder; the row-fit column distinguishes direct RTF evidence from supporting context. Values are pulled directly from cited sources without re-aggregation.
| Analyte | Row-fit | Reported concentration | Detection note | Sources | Source coverage | Basis |
|---|---|---|---|---|---|---|
| lead (Pb) | infant formula, form not separated | weighted mean difference (WMD) 42.98 µg/kg (95% CI 7.60-78.36; N=8 studies); stage 1+2 medians 15 µg/kg each; cow-milk formula median 5 µg/kg; Iranian market below LOD (0.01 mg/kg); range across individual studies 3.80-119 µg/kg | detected in 74% of infant formula items (Collado-Lopez 2026); below LOD in all Iranian market samples (Rahati 2026) | 5 cited | medium (5 sources) | powder as placed on market (most); prepared-for-feeding or as-sold |
| lead (Pb) | direct row-fit (RTF/liquid) | blood lead at 8-196 days old in formula-fed infants supplied RTF in glass bottles: mean 8.9 µg/dL at 8 d, 5.1 µg/dL at 56 d, 5.4 µg/dL at 84 d, 6.1 µg/dL at 140 d (exposure biomarker, not product concentration) | measured at multiple time points, Ryu 1983 cohort | 1 cited | low (1-2 sources) | blood biomarker (as consumed) |
| cadmium (Cd) | infant formula, form not separated | WMD 4.13 µg/kg (95% CI 2.86-5.41; N=9 studies); soy-based median 1 µg/kg; stage 1 range 0.50-60.0 µg/kg; Iranian market below LOD (0.03 mg/kg) | detected in 61% of infant formula items (Collado-Lopez 2026); below LOD in Iranian market (Rahati 2026) | 4 cited | medium (4 sources) | powder as placed on market (most); as-sold |
| inorganic arsenic (iAs) | infant formula, form not separated | WMD 12.2 µg/kg (95% CI 5.66-18.74; N=10 studies) in infant formula; American region WMD 22.41 µg/kg; European region WMD 9.30 µg/kg | below EU 20 µg/kg ML in global pooled estimate; speciated iAs in a minority of included studies | 2 cited | low (1-2 sources) | powder as placed on market |
| total arsenic (tAs) | infant formula, form not separated | without-stage formula median 52 µg/kg; stage 1 range 0.35-15.0 µg/kg; Iranian market mean 1 mg/kg (equals FAO/WHO limit for Al, not tAs — see note) | detected in 63% of infant formula items (Collado-Lopez 2026); 72% of without-stage formula items exceeded As ML used by authors | 3 cited | medium (3 sources) | as-sold (dry weight) |
| methylmercury (MeHg) | infant formula, form not separated | WMD 10.26 µg/kg (95% CI 0-29.52; N=3 studies) in infant formula; below LOD in all Iranian market samples | substantial heterogeneity (I² > 90%); N=3 studies in meta-analysis pool | 2 cited | low (1-2 sources) | powder as placed on market |
| total mercury (tHg) | infant formula, form not separated | below LOD in Iran (LOD 0.012 mg/kg) and in Brazil (LOD 0.003 mg/kg); below LOD or trace in Ghana (mean 0.001 mg/kg) | below LOD in multiple markets; total Hg not methylmercury | 3 cited | medium (3 sources) | as-sold (powder or mixed baby foods) |
| aluminum (Al) | infant formula, form not separated | WMD 946.75 µg/kg (95% CI 169.35-1724.14; N=10 studies) in infant formula; mean 1000 µg/kg (Iran market); 432-1241 µg/kg (Brazil) | 100% detected where reported; substantial inter-study variability | 3 cited | medium (3 sources) | powder as placed on market |
| chromium (Cr) | infant formula, form not separated | WMD 250.37 µg/kg (95% CI 148.97-351.77; N=10 studies) in infant formula; mean 500 µg/kg (Iran market, total Cr); preterm formula mean 0.03 µg/mL | total Cr reported; Cr-VI not speciated in any cited source | 3 cited | medium (3 sources) | powder as placed on market; as-sold |
| nickel (Ni) | infant formula, form not separated | WMD 131.14 µg/kg (95% CI 0-336.7; N=4 studies) in infant formula; maximum 17 µg/kg in Polish powder formulas (Dobrzynska 2025); EDI from Ni exceeded EFSA LOAEL (4.3 µg/kg body weight) for eczematous reactions in all formula categories at 1-6 months | Ni detected in 62 of 149 Polish formula samples | 2 cited | low (1-2 sources) | powder as placed on market |
| Se | infant formula, form not separated | WMD 180.64 µg/kg (95% CI 132.21-229.06; N=19 studies) in infant formula; Polish market median 4.9 µg/100 kcal (total Se); dominant species are selenite and selenate; trace selenomethionine and methylselenocysteine also detected | Se concentrations in 78.4% of Polish formulas within EU limits; 6 of 148 formulas had EDI exceeding tolerable upper intake level | 2 cited | low (1-2 sources) | powder as placed on market; per-100-kcal |
| tin (Sn) | infant formula, form not separated | Polish market median 0.3 µg/kg (IQR 0.1-0.5) in infant formula; range 0-2.2 µg/kg; well below Sn limit of 50,000 µg/kg | Sn detected at trace levels | 1 cited | low (1-2 sources) | powder as placed on market (wet weight) |
| uranium (U) | infant formula, form not separated | WMD 3.19 µg/kg (95% CI 1.61-4.77; N=16 studies) in infant formula; Brazilian market 2-16 µg/kg | detected consistently across global samples | 2 cited | low (1-2 sources) | powder as placed on market |
Limits applicable to this category
Ready-to-feed infant formula does not have a universally applied separate regulatory maximum level in most jurisdictions. The EU Regulation 2023/915 sets limits on infant formula placed on the market as powder; RTF and concentrated liquid are covered under different or absent separate limits in most instrument text. Where applicable powder-basis limits are cited for context, the basis difference is noted.
| Instrument | Metal | Value | Basis note |
|---|---|---|---|
| EU Regulation 2023/915 | Lead | 20 µg/kg | Powder as placed on market; RTF has no separate EU ML in this instrument. |
| EU Regulation 2023/915 | Inorganic arsenic | 20 µg/kg | Powder as placed on market; RTF has no separate EU ML in this instrument. |
| EU Regulation 2023/915 cadmium | Cadmium | 10 µg/kg | Powder as placed on market; RTF has no separate EU ML in this instrument. |
Federal and regulatory limits versus field findings
| Metal | Regulatory limit | Field finding | Decision read | Evidence |
|---|---|---|---|---|
| Lead lead (Pb) | EU Regulation 2023/915: 20 µg/kg Pb. Scope: infant formulae as powder placed on market. No separate EU RTF ML. | Global meta-analysis WMD 42.98 µg/kg (95% CI 7.60-78.36; N=8 studies) in infant formula powder; cow-milk formula median 5 µg/kg. RTF as-consumed values not directly reported. | Indicative. The global meta-analysis WMD for lead in infant formula powder exceeds the EU 20 µg/kg ML, driven largely by high-concentration regional outliers. The cow-milk formula median at 5 µg/kg falls below the EU cap. RTF is consumed at approximately 1:7 dilution vs powder basis, so if the product is formulated from reconstituted powder, as-consumed lead concentrations are substantially lower than powder-basis values. No direct RTF as-consumed lead product data were identified in this deposit. | Essential and Potentially Toxic Elements in Commercial Milk Formulas: Health Risk Assessment Through a Systematic Review and Meta-analysis; Concentrations of Heavy Metals in Processed Baby Foods and Infant Formulas Worldwide: A Scoping Review |
| Cadmium cadmium (Cd) | EU Regulation 2023/915: 10 µg/kg Cd. Scope: infant formulae (cow milk proteins) as powder. No separate RTF ML. | Global meta-analysis WMD 4.13 µg/kg (95% CI 2.86-5.41; N=9 studies) in infant formula powder; global pooled estimate below EU cap. | Below cap on global pooled estimate. Regional outliers exist: stage 1 range up to 60.0 µg/kg in Saudi Arabian market samples. The EU cap (powder basis) is not directly applicable to RTF. | Essential and Potentially Toxic Elements in Commercial Milk Formulas: Health Risk Assessment Through a Systematic Review and Meta-analysis; Occurrence and dietary exposure assessment of heavy metals in baby foods in the Kingdom of Saudi Arabia |
| Arsenic, Inorganic inorganic arsenic (iAs) | EU Regulation 2023/915: 20 µg/kg iAs. Scope: infant formulae as powder. No separate RTF ML. | Global meta-analysis WMD 12.2 µg/kg (95% CI 5.66-18.74; N=10 studies) in infant formula. American region WMD 22.41 µg/kg exceeds the 20 µg/kg cap. | Mixed. Global pooled estimate (12.2 µg/kg) is within the EU 20 µg/kg cap. The American region WMD (22.41 µg/kg) exceeds it. The cap applies to powder basis; most studies measured total arsenic and treated it as a proxy for inorganic arsenic. Direct iAs speciation was minority practice in the included studies. | Essential and Potentially Toxic Elements in Commercial Milk Formulas: Health Risk Assessment Through a Systematic Review and Meta-analysis |
Product context
Ready-to-feed (RTF) liquid infant formula has usable but limited direct heavy-metal occurrence evidence. Most published occurrence data were collected from powdered formula without separating RTF from powder forms. Structured rows below report what the literature records; they do not establish certification limits.
- Evidence status: moderate, with 13 recent peer-reviewed papers; most report infant formula broadly without separating RTF from powder.
- Main concern: infants consuming RTF formula are the exposed population; arsenic, lead, cadmium, and aluminum are the best-evidenced metals.
- RTF-specific signal: one prospective cohort (Ryu 1983, in the O'Connor 2026 systematic review) enrolled formula-fed infants supplied RTF product in glass bottles and measured blood lead at multiple time points, providing a rare RTF-labeled early-life lead-exposure dataset.
This page is the public evidence page for ready-to-feed liquid infant formula. Ready-to-feed formula is supplied in bottles or cans as a liquid that requires no water reconstitution before feeding. That distinguishes it from powdered formula, which requires reconstitution, and from concentrated liquid formula, which requires dilution. The heavy-metal basis that applies to RTF is as-consumed liquid (not powder as placed on the market), and all concentration values on this page are interpreted in that context.
Most peer-reviewed literature on infant formula metal concentrations uses mixed sampling frames that combine RTF and powder, or reports powder-basis values only. This page labels each row by the evidence fit to the RTF format. Rows marked “direct row-fit” are from studies that explicitly measured or identified RTF or liquid formula. Rows marked “infant formula, form not separated” are from studies that measured infant formula generally without splitting by form; they are included as supporting context but are not direct RTF occurrence evidence.
RTF-specific exposure signal
The clearest RTF-specific signal in this deposit comes from the O’Connor et al. 2026 series of systematic reviews, which identified the Ryu et al. 1983 study. In that non-randomized trial, infants were enrolled at 6 to 9 days old and supplied commercially available ready-to-feed formula in 67 kcal/dL glass bottles until 111 days old. Blood lead was measured by flameless atomic absorption spectrophotometry. Formula-fed infant blood lead was 8.9 µg/dL at 8 days (n=23), declining to 5.1 µg/dL at 56 days and reaching 6.1 µg/dL at 140 days when some infants received milk-based formula in quart cans. The O’Connor 2026 systematic review rated the analytical method as “acceptable.” This is a blood biomarker, not a product concentration, and was collected in 1975-1976. It is included here because it is the only RTF-specific feeding-mode study identified in this deposit.
The Pikounis et al. 2024 urinary biomarker study from the New Hampshire Birth Cohort measured urinary arsenic in US infants at 6 weeks of age. Exclusively formula-fed infants (n=44) had a geometric mean urinary arsenic of 0.85 µg/L (95% CI 0.66-1.09), compared with 0.17 µg/L (0.15-0.18) in exclusively breastfed infants (n=338). This was a 5-fold higher arsenic exposure. The study measured urinary arsenic (inorganic arsenic plus metabolites), which reflects total dietary arsenic exposure from formula plus any water used for reconstitution. The Pikounis study did not distinguish RTF from powder-reconstituted formula.
What remains uncertain
No direct ICP-MS measurements of heavy-metal concentrations in RTF infant formula products were identified in this deposit. All quantitative occurrence rows derive from studies of powdered infant formula or of infant formula without form separation. The RTF-specific evidence is limited to two biomarker studies (Ryu 1983 blood lead, Pikounis 2024 urinary arsenic) that do not provide product concentration data. The form of formula consumed (RTF versus reconstituted powder) was not distinguished in most cited studies. Direct product-level concentration data for RTF liquid formula, speciated inorganic arsenic in RTF, and methylmercury in RTF are all data gaps.
Selenium speciation data are available for Polish-market powder formulas (Dobrzynska 2026): selenite and selenate dominated; selenomethionine and methylselenocysteine were detected as trace organic species. No equivalent speciation data for RTF formula were identified.
Nickel concentrations in Polish-market powder formulas reached 17 µg/kg in the highest sample; estimated daily intake from nickel exceeded the EFSA eczematous-reaction LOAEL (4.3 µg/kg body weight per day) for all formula categories at 1 to 6 months (Dobrzynska 2025). Whether this finding extends to RTF liquid formula is unknown.
Related records
- Infant Formula, RTF Liquid (Non-Soy)
- Infant Formula, RTF Liquid (Soy-Based)
- Infant Formula, Powder (Non-Soy)
- Infant Formula
Methodology
This page reports what the cited sources say about heavy-metal concentrations in ready-to-feed liquid infant formula. The methodology rules below govern all summary tables.
Speciation is treated as non-substitutable. Inorganic arsenic and total arsenic are reported separately; the toxicology and regulatory ceilings differ. Methylmercury and total mercury are reported separately for the same reason. Total chromium is not interpreted as hexavalent chromium unless the source explicitly speciates hexavalent chromium.
Basis is preserved and labeled, never silently converted. RTF formula is consumed as supplied liquid. Where a cited source reports powder-basis concentrations, that basis is noted. Conversion to as-consumed liquid (approximate factor 1:7 powder to water) is shown as indicative only where useful for comparison, not as a direct value.
Non-detect handling. Where a source reports a value below its limit of detection (LOD) or limit of quantification (LOQ), this page preserves the source’s handling. Non-detect findings are listed with the LOD value and are not substituted with zero or half-LOD without attribution.
Source pooling is avoided. Aggregate statistics are not computed by pooling sample values across sources whose LOQs, sampling periods, geographies, and analytical bases differ. Where the page reports summary statistics, those are the source’s own.
Row-fit labeling. Matrix-axis labels are “direct row-fit” when the source explicitly identifies RTF or liquid formula. Labels are “infant formula, form not separated” when the source uses a broad term or does not split by form. Format-axis determines whether a source contributes direct evidence or supporting context.
Evidence tiers. A-tier sources are peer-reviewed primary studies, government reports, and authoritative systematic reviews and meta-analyses. B-tier sources are industry white papers, NGO reports, and trade publications. C-tier sources are news, blog, and press material. Every source cited on this page is A-tier.
Source coverage. Low denotes 1–2 contributing sources, medium 3–10, and high more than 10. These counts describe coverage, not study quality, agreement, or scientific confidence.
Scope caveat from the evidence deposit. Most papers in this deposit survey infant formula as a category without separating RTF from powder. No FDA Total Diet Study, EFSA, FSANZ, Consumer Reports, or brand COA data are included in this deposit. All 13 papers are peer-reviewed open-access publications.
Evidence governance
This page summarizes source-backed occurrence evidence, exposure estimates, and data gaps for ready-to-feed liquid infant formula. It does not publish or justify HMT&C certification limits. All values on this page are literature evidence from the 13 papers deposited under HMI-PROD-ready-to-feed-formula-1.
Evidence deposit: HMI-PROD-ready-to-feed-formula-1. Deposited 2026-11-03. Papers: 13. Builder: Reed Holloway.
Sources
Source records associated with this topic. Inclusion does not establish that every finding applies to this product or ingredient. References above identify works cited in the text.
| # | Citation | Year | Type | Used on this page for |
|---|---|---|---|---|
| 1 | Dobrzynska et al. 2026. Selenium Concentration and Speciation in Formulae for Infants: Implications for Infant Health, Foods | 2026 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 2 | Largueza et al. 2026. Essential and Potentially Toxic Elements in Commercial Milk Formulas: Health Risk Assessment Through a Systematic Review and Meta-analysis, Biological Trace Element Research | 2026 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 3 | Latif et al. 2026. Mineral Profiling of Preterm, Term Breast Milk, and Commercial Infant Formula: Evaluating Nutritional Adequacy for Premature Neonates, Preventive Nutrition and Food Science | 2026 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 4 | Mgbemena et al. 2026. Nutrient exploration and heavy metal risk assessment of baby milk and infant formulae sold within Umuahia metropolis, Nigeria, Scientific Reports | 2026 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 5 | O’Connor et al. 2026. Bioavailability of and US Infant Exposure to Arsenic, Cadmium, Lead, Mercury, and Per- and Polyfluoroalkyls from Human Milk and Infant Formula: Results from a Series of Systematic Reviews, Advances in Nutrition | 2026 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 6 | Rahati et al. 2026. Monte Carlo simulation approach for health risk analysis of heavy metals’ contamination in infant formula and food on the Iranian market, Journal of Health, Population and Nutrition 45:13 | 2026 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 7 | Collado-Lopez et al. 2025. Concentrations of Heavy Metals in Processed Baby Foods and Infant Formulas Worldwide: A Scoping Review, Nutrition Reviews | 2025 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 8 | Dobrzyńska et al. 2025. Analysis of the Elemental Composition of Milk Formulae: Impact on the Nutritional Status of Infants From Birth to 1 Year of Age, Biological Trace Element Research | 2025 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 9 | Thoerig et al. 2025. Assessment of arsenic, cadmium, lead, mercury, and per- and polyfluoroalkyl substances concentrations in human milk and infant formula in the United States: a systematic review, The American Journal of Clinical Nutrition | 2025 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 10 | Pikounis et al. 2024. Urinary biomarkers of exposure to toxic and essential elements: A comparison of infants fed with human milk or formula, Environmental Epidemiology | 2024 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 11 | Alharbi et al. 2023. Occurrence and dietary exposure assessment of heavy metals in baby foods in the Kingdom of Saudi Arabia, Food Science & Nutrition | 2023 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 12 | Amarh et al. 2023. Health risk assessment of some selected heavy metals in infant food sold in Wa, Ghana, Heliyon | 2023 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
| 13 | Almeida et al. 2022. Toxic Metals and Metalloids in Infant Formulas Marketed in Brazil, and Child Health Risks According to the Target Hazard Quotients and Target Cancer Risk, International Journal of Environmental Research and Public Health 19(18):11178 | 2022 | Peer-reviewed | Contribution to this topic remains under review; see the source record for its reported scope. |
Update history
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