Overview
Caridi and colleagues analyzed eleven types of retail flour, five samples each, for potassium-40 and cesium-137 activity, cadmium and lead by ICP-MS, and nine minerals including nickel. Table 4 gives one mean cadmium and lead value per flour type, all below the EU thresholds the authors cite. The radiological dose from flour was well under 1 mSv per year.
Key numbers
- Chestnut flour: cadmium “0.070” mg/kg, the highest of the eleven types (Table 4, p. 9).
- Corn flour: lead “0.18” mg/kg; wholemeal and oat flour: lead “0.17” mg/kg (Table 4).
- Oat flour: nickel “2.5” mg/kg (Table 5, p. 10).
Methods (brief)
Samples were microwave digested in nitric acid and hydrogen peroxide; cadmium and lead were measured by ICP-MS in collision-cell mode and minerals by ICP-OES and ICP-MS. Calibration used aqueous reference materials. No food reference material, recoveries or detection limits are reported for the metals.
Evidence Fitness
Means of five samples per flour without SDs, detection limits or matrix-matched QA. Calibrations were also prepared for arsenic and mercury, but no results are reported for them. Flour is used as a thickener, so this is only a proxy for brown-gravy, and that page is not linked. Direct evidence for wheat and rice flours.