Metal contamination

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  • 1. • Food contamination : “The presence in food of harmful chemicals and microorganisms which can cause consumer illness”. • not been intentionally added to food. • Contaminants foods 1.various stages of its production& Packaging 2. From the environment • Negative impact on the quality of food
  • 2. • Around 80 of the 103 elements listed in the periodic table are metals. • How to differentiate between metallic and non-metallic elements by their physical characteristics • The presence of the metals have both good and bad effects Metallic Non metallic typically solids may be gases, liquids electrically conducting non-conducting lustrous Not lustrous Malleable & ductile Almost not like that
  • 3. • There can be considerable variations in the concentration of metals even with in the same class of food, depending on its topographical origins and other factors. • Metals may not be distributed evenly within a single sample of a food. • Milling affects the metals concentration • Eg:. A whole grain of wheat can contain 7.4µg copper/g ,but with only 2.0µg/g of this is in endosperm
  • 4. • We consume only a small number of metals. These are a believed to essential for normal life. • Insufficient intake of any one of these essential inorganic nutrients Specific biochemical lesions with cells of the body Development of characteristic clinical symptoms
  • 5. Nutrients and other metals Toxic metals eg: Cd,Pb,Hg Nutrient metals Micro nutrients e.g: Cr ,Cu, Mo Macro nutrients e.g: Ca ,Mg, Na, K Non toxic ,non essential eg : Al,Sn
  • 6. • Not always possible to make toxic ability • Play essential roles in human metabolism and body functional • Single metal difficult to consider toxicity • If the metals are consumed together, they are capable of interacting with other metals and give toxicity. • Eg:Toxicity of cadmium , are closely related to the amount of zinc present
  • 7. • Traces metals can cause quality changes in foods during cooking and storage • changes in food by metal contamination. • Eg: 1. Fe + Anthocyanin black pigment in certain fruit 2. Iron affect the sensory qualities of liquid foods and loss of odor , bitter tastes 3. Traces metals oxidation of unsaturated fatty acids
  • 8. • The term heavy metal is - high specific gravity -have a strong attraction to biological tissues -have slowly eliminated from biological system Eg: Pb,Hg,Se,Cd,As
  • 9. Pb • Concentrations of lead in different food products vary greatly • Lead in food creates mainly from atmospheric deposition and adherence of lead-rich soil particles to plants • The content of lead plant foodstuffs > animal foodstuffs
  • 10. As • The consumption of As by humans reflects the quantities of seafood in the diet. • occurs mainly in the organic form Hg • The toxicity of mercury -elemental, inorganic and organic in form • more dangerous organic form> inorganic form or elements
  • 11. • Inorganic and organic are found in food. • Main source of the mercury -fish and other aquatic animals • Mostly affected by Hg -pregnant and breast feeding women • How metals get into food Metals Food 1. Industrial contamination(during the processing , packaging ,catering operation) 2. Up take metals by the plant 3. Food fortification 4. Geophagia
  • 12. • The legislation is the rule of law that keeps a country going smoothly and provides for law and orders it’s abused at times • Codex Aliment Arius Commission of FAO/WHO publish The food safety act and each countries nutrient labeling and education act
  • 13. Food cadmium levels(mg/kg) Chocolate and cocoa products 0.5 Kidney (cattle,sheep,pig) 2.5 Liver (cattle,sheep,pig) 1.25 Meat (cattle,sheep,pig) 0.05 Molluscs 2.0 Peanuts 0.1 Rice 0.1 Vegetable(leafy) 0.1 Vegetable(root and tuber) 0.1
  • 14. Food lead levels(mg/kg) Brassicas 0.3 Cereals ,pulses ,legumes 0.2 Offal (cattle ,sheep ,pig poultry ) 0.5 Fish 0.5 Fruit 0.1 Infant formula 0.02 Meat (cattle ,sheep,pig,poultry) 0.1 Molluscs 2.0 Vegetables (other) 0.1
  • 15. sampling Preparation of samples Analysis of the samples Collect the data Presentation of data