POTASSIUM ALUMINIUM SILICATE-BASED PEARLESCENT PIGMENTS
(TENTATIVE)
New tentative specifications prepared at the 74th JECFA (2011) and published in FAO Monographs 11 (2011). A PTWI of 2 mg/kg bw for aluminium was established at the 74th JECFA (2011). An ADI ‘not limited’ was established for titanium dioxide at the 13th JECFA (1969) and an ADI of 0-0.5 mg/kg bw was established for iron oxides at the 53rd JECFA (1999).
Information required:
• On the manufacture of all types of potassium aluminium silicatebased pearlescent pigments currently used in food.
• On the stability of potassium aluminium silicate-based pearlescent pigments in food.
• Suitable description for inclusion in the specifications monograph for the three versions of potassium aluminium silicate-based pearlescent pigments used in food: 1) potassium aluminium silicate with titanium dioxide; 2) potassium aluminium silicate with iron oxide; 3) potassium aluminium silicate with titanium dioxide and iron oxide).
• On the complete particle size distribution for all available types of potassium aluminium silicate-based pearlescent pigments used in food.
• On the pH of a 10% aqueous slurry for each type of potassium aluminium silicate-based pearlescent pigment available for use in food.
• Method for the identification of iron, titanium and aluminium in potassium aluminium silicate-based pearlescent pigments.
• Data from the analysis of five batches of each type of potassium aluminium silicate-based pearlescent pigment available for use in food for the following contaminants: arsenic, mercury, lead, antimony, cadmium, zinc, barium, chromium, copper and nickel.
• Method for the determination of lead, antimony, cadmium, zinc, barium, chromium, copper and nickel in potassium aluminium silicate-based pearlescent pigments using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Indicate if the method involves digestion or only extraction of the impurities from the sample.
• Suitability of proposed method for the determination of mercury using digestion under a closed system followed by a cold vapour generation technique and analysis with atomic absorption spectrometry.
• Suitability of proposed Assay method which incorporates alkali fusion coupled to ICP-AES for the determination of the percentage
of titanium, iron and aluminium.
• If x-ray fluorescence is preferred for the Assay for titanium dioxide and iron oxide, provide a detailed description of the method, validation data, and data from the analysis of 5 batches for each type of pigment.
• Specific filtration methods for pigments with particle sizes below 60 micrometers.
