The objective was to quantity iodine losses during transit and storage from production to retail end over 12 monthsto inform the policy.
In this field based study, we measured in duplicate iodine content in salt using iodometric titration method of 450 samples at the inception of the study and 443 samples at 12 months, produced though routine production process and transported through road. The samples included a range of following combinations: Salt produced in 8 geographic areas considering the unique chemical composition of brine; 5 types of processed salt; 4 processing methods; three types of packing material; packed in 1kg or 50kg bags and stored in 6 geo-climatic zones across the country.
The salt samples were iodized at 30 ppm (±2 ppm) with average iodine content at the inception was 30.84 ppm (±3.64 ppm SD) and 28.50 (±6.46 ppm SD) at 12 months, indicating a loss of 2.34 ppm (8%) over the study period. The highest loss was in salt packed in LLDPE bags at 2.91 ppm with average iodine content on inception at 31.08 (±4.09 ppm SD) and 28.50 (±5.46 ppm SD) at 12 months.
The findings indicated an average iodine loss of 8% over 12 months, suggesting a need to relook at the existing standard of 30 ppm at production end and 15 ppm at the retail end, which assumes 100% loss during movement of salt from production unit to retail end.