Stability of Iodine in Iodized Salt L.L.Diosady1 and M.G

Since iodine readily sublimes at ambient temperature, the effectiveness of salt iodization programs depends on the stability of the iodine carrier, typically potassium iodate. We examined the stability of iodine in typical salts available in 12 countries in a controlled laboratory setting, at high temperature (40°C) and controlled humidity (60 or 100%) for periods up to 12 months. Iodine was rapidly lost in most unrefined salt samples. The presence of moisture, due to hygroscopic impurities, and metal ion impurities, such as iron accelerated the loss of iodine. Packaging in a moisture-proof continuous film package significantly increased the iodine retention in all samples.