Overview
Nachman and colleagues bought chicken breast in 10 US cities in 2010 and 2011, before roxarsone sales were suspended, and measured total arsenic and arsenic species in raw and baked meat. Conventional chicken had higher inorganic arsenic than antibiotic-free or organic chicken, and samples with detectable roxarsone had about three times the inorganic arsenic of roxarsone-negative samples. Baking raised total and inorganic arsenic and lowered roxarsone.
Key numbers
- Cooked chicken, all samples: total arsenic geometric mean 3.0 µg/kg (95% CI 2.5 to 3.6, n = 140); inorganic arsenic 1.1 µg/kg (n = 78) (Table 2).
- Cooked inorganic arsenic by label: conventional 1.8, antibiotic-free 0.7, organic 0.6 µg/kg (Table 2).
- Roxarsone-positive vs negative cooked samples: inorganic arsenic 2.3 vs 0.8 µg/kg (Table 2).
- Paired raw vs baked breast: inorganic arsenic 0.8 to 1.1 µg/kg (+27.2%); roxarsone 1.8 to 1.0 µg/kg (-44.1%) (Table 4).
Methods (brief)
One breast per package was split into a raw half and a half baked to 75 °C internal temperature. Freeze-dried tissue was analyzed for total arsenic by ICP-MS, and samples with at least 10 µg/kg dry-weight total arsenic were speciated by HPLC-ICP-MS. Results were converted to wet weight. LODs were 1 µg/kg dry weight (2 µg/kg for roxarsone). Accuracy was checked with SRM 1568a and in-house rice and chicken reference materials.
Evidence Fitness
A strong, well-documented national retail sample with speciation and paired raw and cooked data. Speciation covers only the higher-arsenic subset, and results reflect practices before roxarsone was withdrawn in the US in 2011, so current conventional chicken may be lower. This is the peer-reviewed article; the research brief record covers the same study. Direct evidence for meat-and-poultry; for chicken broth and chicken noodle soup it is a chicken meat proxy only.