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Food preservation


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Published in: Health & Medicine
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Food preservation

  1. 1. Preservation usually involves preventing the growth of bacteria, yeast, fungi and other micro organisms.
  2. 2. “A process by which foods like fruits and vegetables are prevented from getting spoil for a long period of time. The colour, taste and nutritive value of food is also preserved”
  3. 3. 1. Presence of microorganism Situations for the appropriate growth of micro organisms-  Food having high moisture content  Air around the food containing microorganisms  Foods kept for long time at room temperature  Skin of fruits and vegetables getting damaged  Foods with low salt, sugar and acid content
  4. 4. 2. Presence of enzymes
  5. 5. 3. Insects ,worms and rats
  6. 6. 1. Removal of microorganism or inactivating them This is done by removing air, water, lowering or increasing temperature, increasing the concentration of salt or sugar or acid in foods.
  7. 7. 2. Inactivating enzymes -by changing conditions such as temperature and moisture 3. Removal of insects, worms and rats -by storing foods in dry, air tight containers
  8. 8. 1. Drying –removing the foods water Sun drying Commercial drying
  9. 9.  Conventional; - heat  Vaccum; - pulls the water out  Osmotic;- water drawn out by osmosis  Freeze drying; - ice crystals vaporize  Cure –to preserve foods through the use of salt and drying, sugar, spices or nitrates may also be added
  10. 10. Vinegar Edible coating-natural wax, oil, petroleum based wax
  11. 11. The elimination of all micro organisms through extended boiling or through the use of certain chemicals.
  12. 12. Refrigeration Freezing
  13. 13. Pasteurization- heat liquids to 160 degree celsius for 15 seconds Ohmic heating- electrical current is passed through the food generating enough heat to destroy micro organisms.
  14. 14. Low doses of gamma rays, x rays, or electrons
  15. 15. Exposes food to intense, very brief flashes of light which disrupt the cell membrane of bacterial cells.
  16. 16. Inactivates food borne micro organisms at low temperature
  17. 17. Uses ultra high pressure to inhibit the chemical process of food deterioration.
  18. 18. Ozone is commercially produced by exposing oxygen to electrical current. Ozone is an effective disinfectant
  19. 19. Foods are packaged airtight by a commercial sealing process