Addis Ababa University College of Natural Sciences Center for Food Science and Nutrition Adequacy of Iodine Content and Level of Contaminants in Edible Salts Produced In Ethiopia BY: Henok Araya Advisor: Dr. Ashagrie Zewdu A Thesis submitted to Center for Food Science and Nutrition College of Natural Science of Addis Ababa University in Partial Fulfillment of the Requirements for the Degree of Masters in Food Science and Nutrition January,2016 Addis Ababa, Ethiopia i Contents ACKNOWLEDGMENTS .............................................................................................................. v LIST OF TABLES ......................................................................................................................... vi LIST OF APPENDICES ............................................................................................................... vii ANNEX........................................................................................................................................ viii LIST OF ACRONYMS AND ABBREVIATIONS ...................................................................... ix ABSTRACT ................................................................................................................................... xi 1. Introduction ................................................................................................................................. 1 1.1. Background of the study ...................................................................................................... 1 1.2. Statement of the problem ..................................................................................................... 3 1.3. Objective of the study .......................................................................................................... 4 1.4. Hypothesis ............................................................................................................................ 5 1.5. Significance of the study ...................................................................................................... 5 2. Literature Review........................................................................................................................ 6 2.1. Types of salt ......................................................................................................................... 6 2.1.1. Unrefined salt ................................................................................................................ 6 2.1.2. Iodized salt ..................................................................................................................... 6 2.1.3. Refined salt .................................................................................................................... 6 2.2. Significance of salt ............................................................................................................... 7 2.3. Methods of salt production ................................................................................................... 7 2.4. Iodine .................................................................................................................................... 8 2.5. Iodine deficiency .................................................................................................................. 8 2.6. Iodine Deficiency Disorder (IDD) ....................................................................................... 9 2.7. Iodized salt ........................................................................................................................... 9 2.8. Factor Affecting consumption Iodized salt ........................................................................ 10 2.9. Salt Fortification ................................................................................................................. 11 2.10. Source of heavy metal in the saline water body ............................................................... 13 2.11. Biochemistry of heavy metals toxicity ............................................................................. 13 2.12. Food Safety ...................................................................................................................... 15 2.13. National Codex Committee .............................................................................................. 16 ii 2.14. The Ethiopian Standard Specification for both iodized Common and Table Salts .......... 16 2.15. Risk assessment ................................................................................................................ 17 2.16. Selected heavy metals in salt ............................................................................................ 17 2.16.1. Cadmium ................................................................................................................... 17 2.16.2. Lead ........................................................................................................................... 18 2.16.3. Zinc ............................................................................................................................ 19 2.16.4. Copper ....................................................................................................................... 19 2.16.5. Magnesium ................................................................................................................ 19 2.16.6. Iron............................................................................................................................. 20 2.17. Sodium Chloride .............................................................................................................. 20 2.17. Alkalinity .......................................................................................................................... 21 2.18. Sulphate ............................................................................................................................ 21 2.19. Moisture content ............................................................................................................... 22 2.20. Matter insolubility ............................................................................................................ 22 2.21. pH of the salt .................................................................................................................... 22 2.22. Metal analysis ................................................................................................................... 22 3. Materials and Method ............................................................................................................... 24 3.1. Sampling Areas .................................................................................................................. 24 3.2. Coding of salt samples ....................................................................................................... 24 3.3. Sampling and Sampling Procedure .................................................................................... 24 3.3.1. Method of Sampling .................................................................................................... 24 3.3.2. Study Setting................................................................................................................ 24 3.4. Chemical analysis ............................................................................................................... 25 3.5. Reagent and standard solution............................................................................................ 25 3.6. Determination of moisture content ..................................................................................... 25 3.7. Determination of Alkalinity ............................................................................................... 25 3.8. Determination of sulphate .................................................................................................. 26 3.9. Determination of sodium chloride...................................................................................... 26 3.10. Determination of pH......................................................................................................... 26 3.11. Determination of matter insoluble in water...................................................................... 26 3.12. Apparatus for iodine titration and Determination of iodine ............................................. 27 iii 3.12.1. Preparation of reagents .............................................................................................. 27 3.12.2. Procedure for iodine determination in salt samples ................................................... 27 3.13. Determination of metal impurities ................................................................................... 27 3.13.1. Analysis of metals ..................................................................................................... 28 Validation of analytical methodology (Recovery test) .......................................................... 28 Detection limit ........................................................................................................................... 28 3.13.2. Calibration procedure ................................................................................................ 29 3.14. Statistical analysis ...........................................................................................................