clay and dibenzofuran

Bleaching earth (dried, powdered, bentonite-montmorillonite clay) is commonly used as a processing aid in edible oil refinement. Used bleaching earth may be incorporated into animal feed indirectly, for example because it is included into seed meal, or directly (e.g., as a binding agent). Control must be demonstrated to ensure that the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in feed ingredients do not infringe European Community regulations. The low legislative action level assigned is analytically challenging and may be at or below the limits of quantification achievable by many laboratories. A statistical comparison (following the IUPAC/ISO/AOAC protocol) was made of analyses of PCDDs and PCDFs in selected bleaching earth samples by laboratories from Europe and the USA to assess the comparability of data. Of 19 sets of results submitted by laboratories for replicate samples, 11 demonstrated acceptable agreement.

Topics: Aluminum Silicates; Animal Feed; Animals; Bentonite; Benzofurans; Clay; Dietary Fats, Unsaturated; Europe; Polychlorinated Dibenzodioxins; Reproducibility of Results; Soil Pollutants; United States