Carey et al. 2018 — Rice dilution in UK infant foods after EU 100 µg/kg iAs standard
This PLoS ONE study assessed inorganic arsenic (iAs) concentrations in UK infant rice-based foods and their general (non-infant-labelled) equivalents in 2017, comparing the findings to 2014 and 2016 surveys, in the context of the EU 100 µg/kg iAs standard for infant rice products that came into force 1 January 2016. All 2017 UK products specifically labelled for infants fell below the 100 µg/kg threshold. Pure rice infant porridge had a median of 66 µg/kg (down from 114 µg/kg in 2016 and 127 µg/kg in 2014); multi-grain infant porridge had a median of 10 µg/kg, illustrating that blending rice with maize, oats, quinoa, or potato as a formulation strategy has been broadly adopted. General-market rice cakes had a median of 120 µg/kg — above the infant standard — demonstrating that non-infant-labelled products remain a risk vector for young children.
Key numbers
- 2017 survey products: range of UK infant foods and general-market equivalents, n not broken down per product class in abstract (total ~106 products across all sampling points)
- LOD for iAs and DMA: 1 µg/kg; below-LOD values assigned half-LOD
- CRM NIST SRM 1568b recoveries: DMAA 103.4% (RSD 8.3%), MMAA 94.5% (RSD 10.4%), iAs 83.7% (RSD 12.7%), sum of species 96.6% (RSD 9.3%)
- Infant products: pure baby rice porridge median 66 µg/kg (n = 6); multi-grain infant porridge median 10 µg/kg (n = 15); baby rice cake median 60 µg/kg (n = 2); baby multi-grain cake median 8 µg/kg (n = 10)
- All infant-labelled products fell below EU 100 µg/kg limit
- Temporal trend in infant porridge: 127 µg/kg (2014) → 114 µg/kg (2016) → 66 µg/kg (2017); statistically significant (P = 0.0393)
- General-market products: general rice cakes median 120 µg/kg (n = 14; 13 of 14 contained wholemeal rice); general white puffed rice median 95 µg/kg; wholemeal puffed rice median 140 µg/kg — highest of any product class
- Rice content vs. iAs correlation: R² = 0.632, P < 0.0001 across all infant foods
- Multi-grain porridges: median iAs as low as 9.75 µg/kg, ~10-fold below the 100 µg/kg EU limit
- EU adult standard for polished white rice: 200 µg/kg; EU limit for puffed rice: 300 µg/kg
- Authors’ dose estimate: 20 g serving of a 100 µg/kg product → 0.22 µg/kg BW per sitting for a 9.25 kg 1-year-old, exceeding adult 3 µg/L water dosing by 5-fold
Methods (brief)
Retail survey, UK (24 stores across Northern Ireland: Enniskillen, Craigavon, Lisburn, Belfast) in 2017; duplicate or triplicate samples of each product from separate retail outlets. Arsenic speciation by IC-ICP-MS (Thermo Dionex IC5000 + Thermo ICAP-Q); anion exchange (IonPac AS7, 2×250mm) with ammonium carbonate mobile phase; 95°C microwave digestion in 1% HNO₃; species calibrated against DMA. Statistical: Mann-Whitney U and Kruskal-Wallis; GraphPad Prism v6.
Limitations
UK-only survey; 24 stores concentrated in Northern Ireland. Small n for pure baby rice cakes (n = 2 in 2017) precludes statistical analysis of that subcategory. Only 4 products declared rice country of origin; manufacturer sourcing strategies not verifiable. Does not provide season-of-purchase breakdown. Mycotoxin risk in alternative grains (maize, oats) noted as an unresolved trade-off not addressed by this study.
Implications
- Certification: Strongly supports HMT&C’s multi-grain product assessment framework. Shows that post-EU-regulation infant-labelled products broadly comply, but that non-infant-labelled equivalents routinely exceed 100 µg/kg — meaning certification scope matters for brand legal exposure. Multi-grain blending is a verified mitigation strategy achieving 10-fold reduction.
- Courses: Exemplary case study for how regulatory standards drive formulation change; also illustrates the loophole created when standards apply only to labelled infant products.
- App: iAs in pure rice infant products clustered 60–66 µg/kg (infant-labelled); general puffed rice wholemeal at 140 µg/kg is among the highest rice-based exposures measured in a market survey. Multi-grain products with rice as one of several grains trend well below 25 µg/kg.
- Microbiome: Not primary topic.