Metal contamination

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Metal contamination

  1. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 15. sampling Preparation of samples Analysis of the samples Collect the data Presentation of data

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