Key Numbers
Brown rice syrup products (n=3, retail samples):
- Total As (tAs): 78–406 ng/g (mean 203 ng/g)
- Inorganic As (iAs): 71–355 ng/g, representing 91–94% of total As
- Dimethylarsenate (DMA): 6–41 ng/g (minor contribution)
Infant formula with organic brown rice syrup (n=2, retail products):
- tAs: 10–177 ng/g in reconstituted liquid formula
- Approximately 20-fold higher As concentration than non-OBRS formulas tested in parallel
Infant formula without brown rice syrup (comparison group):
- tAs: 5–9 ng/g in reconstituted liquid (baseline)
Cereal and cereal-based products (n=29 samples):
- Breakfast cereals: 8–128 ng/g
- Cereal bars with brown rice: As concentrations paralleled OBRS content
Energy/protein products containing brown rice (n=3):
- tAs: 84–171 ng/g
Aluminum (Al) and uranium (U) also measured in select samples; concentrations noted but As was primary analyte.
Methods
Sampling: Retail market survey of US products marketed as “organic” in infant formula, breakfast cereal, cereal bars, and energy-supplement categories (2009–2010 timeframe).
Analytical technique:
- Inductively coupled plasma mass spectrometry (ICP-MS) for total As, Al, U
- Ion-exchange high-performance liquid chromatography coupled to ICP-MS (HPLC-ICP-MS) for As speciation (iAs, DMA, MMA distinction)
Sample preparation:
- Reconstituted formula prepared according to manufacturer instructions for liquid-phase analysis
- Dry products analyzed in situ
- Quality assurance via certified reference materials
Sample size: ~200 individual product samples across all categories; emphasis on brown rice-containing products as primary contamination source.
Implications
This was among the first market-scale surveys linking brown rice syrup (OBRS) addition to formulas with significant As enrichment. The data established that:
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IAs dominance: As in brown rice syrup is predominantly inorganic As (iAs, 91–94%), the form of greatest toxicological concern, with minor contributions from DMA.
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OBRS as a discrete source: The ~20-fold As elevation in formulas with added OBRS versus baseline infant formulas identified OBRS as a specific, addressable ingredient-level source rather than background contamination.
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Dietary exposure relevance: For infants consuming formula with OBRS, the paper provided direct As exposure estimates that later became central to infant-risk assessments in regulatory guidance and certification thresholds.
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Cereal/snack category relevance: Quantification of As in cereal bars and energy products containing brown rice extended the exposure-pathway concern beyond infant formula to broader dietary intake in children and adults.
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Baseline for organic category: The data demonstrated that “organic” labeling did not confer lower As contamination; in fact, OBRS use in organic infant formula resulted in higher As concentrations than conventional formulas.
The study provided foundational evidence for later ingredient-level and product-level contamination syntheses and informed decisions to track OBRS as a distinct risk factor in contamination profiles for infant formula and grain-based products.
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## 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](https://github.com/paleofoundation/heavymetalindex). When DOI minting comes online (see [[../docs/schemas/index.md|schema docs]]), each entry below will also link to a version-pinned DataCite DOI.
| Commit | Date | Change | Description |
| --- | --- | --- | --- |
| [29805d3](https://github.com/paleofoundation/heavymetalindex/commit/29805d3) | 2026-08-02 | major | Contamination-profile values revised; 4 sections added; narrative text revised |
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