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  • Justifying the need to prescribe limits for toxic metal contaminants in food-grade silver foils.

Justifying the need to prescribe limits for toxic metal contaminants in food-grade silver foils.

Food additives and contaminants (2005-12-17)
Mukul Das, S Dixit, S K Khanna
ABSTRACT

The use of silver foils in various food preparations is a common practice in Middle Eastern and South East Asian countries. The FAO/WHO Joint Expert Committee on Food Additives (JECFA) has included silver in the list of food additives, but specifications were not prepared. Indian food legislation has included food-grade silver foil and laid down a purity requirement of 99.9%. This leaves an unspecified margin of 0.1% or 1000 microg g(-1) for contaminants. Therefore, a study to investigate the levels of metallic contaminants in food-grade silver foil was undertaken. Of 178 foils analysed, 161 (90%) contained silver, whilst 10% were fraudulently made up of aluminium. In the case of silver foils, 46% of the samples adhered to the desired purity requirement of 99.9%, while 54% had a lower silver content. Copper was present in 86.3% of the silver foils, while chromium, nickel and lead contamination was found in over 54% of samples. Cadmium levels were detected in 28% of the silver foils and manganese was present in 6.8% of samples. In silver foils showing metal contaminants, average levels were found for nickel (487 microg g(-1)), lead (301 microg g(-1)), copper (324 microg g(-1)), chromium (83 microg g(-1)), cadmium (97 microg g(-1)) and manganese (43 microg g(-1)), which being appreciable justify the need to prescribe limits for some metals in food-grade silver foil as well as for silver powder used in confectioneries and medicinal preparations. The work reported here should encourage manufacturers to use high-purity raw materials and take suitable precautions to reduce unwarranted exposure of consumers to toxic metal contaminants.

MATERIALS
Product Number
Brand
Product Description

Silver, foil, 8mm disks, thickness 0.008mm, 99.97%
Silver, foil, 50mm disks, thickness 0.125mm, as rolled, 99.99+%
Silver, foil, 6mm disks, thickness 0.004mm, 99.97%
Silver, foil, light tested, 100x100mm, thickness 0.05mm, annealed, 99.95+%
Silver, foil, 8mm disks, thickness 0.5mm, as rolled, 99.99+%
Silver, foil, 8mm disks, thickness 0.0125mm, 99.95+%
Silver, foil, 6mm disks, thickness 0.15mm, as rolled, 99.95+%
Silver, foil, 8mm disks, thickness 0.015mm, 99.97%
Silver, foil, 6mm disks, thickness 0.1mm, annealed, 99.95+%
Silver, foil, 6mm disks, thickness 0.01mm, 99.95+%
Silver, foil, 8mm disks, thickness 0.003mm, 99.9%
Silver, foil, 8mm disks, thickness 1.0mm, as rolled, 99.99+%
Silver, foil, 8mm disks, thickness 0.15mm, as rolled, 99.95+%
Silver, foil, 8mm disks, thickness 0.004mm, 99.97%
Silver, foil, light tested, 25x25mm, thickness 0.009mm, 99.97%
Silver, foil, 8mm disks, thickness 0.005mm, 99.97%
Silver, foil, 6mm disks, thickness 0.125mm, as rolled, 99.99+%
Silver, foil, 6mm disks, thickness 0.25mm, as rolled, 99.95+%
Silver, foil, 8mm disks, thickness 0.006mm, 99.97%
Silver, foil, light tested, 50x50mm, thickness 0.05mm, annealed, 99.95+%
Silver, foil, 6mm disks, thickness 0.20mm, as rolled, 99.95+%
Silver, foil, not light tested, 25x25mm, thickness 0.025mm, annealed, 99.95+%
Silver, foil, light tested, 100x100mm, thickness 0.025mm, as rolled, 99.95+%
Silver, foil, 8mm disks, thickness 0.02mm, 99.97%
Silver, foil, light tested, 300x300mm, thickness 0.05mm, annealed, 99.95+%
Silver, foil, not light tested, 25x25mm, thickness 0.008mm, 99.95+%
Silver, foil, light tested, 25x25mm, thickness 0.025mm, as rolled, 99.95+%
Silver, foil, not light tested, 50x50mm, thickness 0.003mm, 99.9%
Silver, foil, light tested, 25x25mm, thickness 0.0125mm, 99.95+%
Silver, foil, 8mm disks, thickness 0.125mm, annealed, 99.95+%