PRESERVATION

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PRESERVATION

• From foukeffa.org
• Written by Teri Micke
• Ag Student Texas AM
• GA Ag Ed Curriculum Office
• To accompany the Georgia Agriculture
  Education Curriculum Lesson 02471-21.2
• June, 2002

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WHAT IS PRESERVATION?

• the treatment of food to keep it from spoiling

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PALATABLE

• an agreeable taste and/or texture

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CONDUCTION

• heating through direct contact
• example roasting marshmellows, grilling
  hamburgers on stove top

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CONVECTION

• heating through water or air
• example boiling water, using oven

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RADIATION

• heated through electromagnetic spectrum
• example microwave

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PASTEURIZATION

• destroy pathogenic microorganisms but not
  spoilage microorganisms
• example milk

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TYPES OF PRESERVATION

• 1. canning - around for over 200 yrs
• 2 ways
• a. hot fill - heated before put in can
• b. canners brine - liquid (sugar/salt mix)
  added

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• 2. Refrigeration - above freezing point 28 to 65
  degrees F short term storage
• 3. Freezing - actually freezing the water in the
  food

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• 4. Drying
• a. mechanical heat (sunlight), wind,
  smoke/heat
• examples grapes to raisins, meat to jerky
• b. freeze drying used by astronauts, just add
  water
• examples milk replacers

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• c. chemical drying
• add salt and sugar
• example ham

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• 5. Fermentation - involves microorganisms (yeast,
  mold, bacteria)
• 2 ways
• a. aerobic with air
• b. anaerobic without air

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• 6. Irradiation expose food to ionizing radiation
  like x-rays, makes food sterile
• veg/spices easy to treat
• meats hard to do, but they are using on
  poultry

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• 7. Food Additives
• examples
• Salt
• Na or Ca - inhibit mold
• Sorbic acid - inhibit yeast/mold, used in
  cheese and fruit drinks

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• Benzoic acid/sodium benzoate - candied products
• BHT/BHA - preserve fat in meat
• Citric acid/tartaric acid - antioxidants (traps
  oxygen)

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WHAT HAPPENS WHEN FOOD FREEZES??

• Example Tomato
• the water in the tomato freezes and forms ice
  crystals which act like sharp pieces of glass and
  puncture cells, the slower the freezing the
  larger the crystals

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WHAT IS FREEZER BURN?

• its the loss of water from the frozen food