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Freezing Food


Freezing Food History The frozen food industry was born in the 1920 s Clarence Birdseye produced the first frozen fish History The industry continued to grow and ... – PowerPoint PPT presentation

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Title: Freezing Food

Freezing Food
  • The frozen food industry was born in the 1920s
  • Clarence Birdseye produced the first frozen fish

  • The industry continued to grow and develop with
    the growth of such technology as fast-freezing
    equipment, home freezers, and the microwave oven
  • The 1950s brought on the TV dinner revolution

The Science of Freezing
  • It preserves food by slowing the action of
    enzymes rather than destroying them

The Science of Freezing
  • Foods that are free of microorganisms when frozen
    will remain so, since most microorganisms cant
    grow at such a low temperature

Freezer Burn
  • Caused by the loss of moisture from food when the
    food is exposed to air
  • Culprit Loose packaging, fluctuation in freezer

Freezer Burn
  • If not packaged properly, even foods that do
    freeze well can experience a damaging effect
  • Foods that are freezer burnt often have a brown
    or grayish color, look very dry, and have a fuzzy
    gray or white spots that look like icy mold

Commercial Freezing
  • Rapid Freezing Process Limited changes in
    color, texture, size and flavor
  • Also, helps foods resist freezer burn
  • Ice crystals are smaller causing less damage to
    food cells

Commercial Freezing
  • Freezing in air is the oldest and still the most
    common method of freezing food, and also the one
    used in home freezing
  • Indirect-contact freezing is food that is placed
    on belts or trays. A refrigerant circulates
    through the wall beside the food and it chills
    quickly and freezes

Commercial FreezingCont
  • Immersion freezing food is submerged directly in
    non-toxic refrigerant to cause quick freezing
  • Most packaging is opaque because many foods lose
    flavor when exposed to light

Home Freezing
  • Storage containers and wraps used for frozen
    foods at home must be moisture proof and airtight
    to maintain quality

Home Freezing
  • Even if it is properly maintained it has a 6-12
    month period before it starts to deteriorate

Home Freezing
  • Foods with high water content, including grapes,
    pears, salad greens, lose shape and texture when
  • Be sure to label and date all packages!!

  • Is a commercial process that combines freezing
    and drying to preserve foods.
  • First food is frozen then its treated to remove
    the solvent from dispersed or dissolved solids.
  • In most food, this means removing the water.
  • Technical name lyophilisation.

  • During freeze-drying, water in the form of ice is
    removed through sublimation occurs on the
    surface and continues inward.
  • Wet clothes on the line during winter example.
  • By the time the ice at the very center has
    sublimed, up to 99 of the foods moisture has
    been removed.
  • The result is dried food.

  • Flash frozen or frozen very quickly a special,
    low-pressure chamber. It is then held at or
    below freezing temperature.
  • The low temperature keeps the water frozen, and
    the low pressure speeds the rate at which ice
    crystals in the food escapes as water vapor.

Using Freeze Dried Foods
  • Foods could be stored for months even years
  • Must be protected in airtight packaging
  • Examples are fruit in cereal and chicken in
    instant soup
  • Makes foods extremely light should be

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Packaging Food
  • Suitable containers
  • Safety needs to be non-toxic and provide a
    sanitary, protected environment
  • Food quality must provide protection from
    light, odors
  • Convenience open easily, resealable, and able
    to pour easily are a
  • Expense lower packaging means lower cost for
    manufacturers and the result is a lower cost to
  • Environmentally safe recyclable containers!
  • Marketing appeal attractive to the consumer!

Packaging Food
  • Modified-atmosphere packaging
  • Called MAP This process creates a specific
    gaseous environment for a food product to
    lengthen shelf life.
  • Used mainly for ready-to-eat products with
    extended shelf lives.
  • Bags of lettuce, baby spinach, and baby carrots
    use this technology in stores!

Packaging Food
  • Aseptic packaging
  • Used for beverages and liquids that have been
    aseptically treated extremely high temperatures
    and contain several layers of material.
  • Containers are not recyclable.
  • Example Drink boxes!

Packaging Food
  • Edible films/wraps
  • Additional film added to apples - Wax
  • Trends in packaging
  • Edible films
  • Smart packaging that tells the consumer a
    number of things if the temperature has ever
    risen enough above the proper temperature the the
    contents of the package may be unsafe to consume
  • Intelligent packaging that tells the consumer
    whether or not the contents are spoiled and may
    not be safe to eat. Ex. A dot that may change

  • One third of the worlds food supply is still
    degraded or destroyed by pests, bacteria, and the
    resulting spoilage.
  • Irradiation food is exposed to a controlled
    amount of radiation (transfer of energy in the
    form of waves) for a specific time to destroy
    organisms that would cause spoilage.

  • Radura Symbol Page 462
  • The FDA (Food and Drug Administration) regulates
    irradiation as an additive.
  • Delaney Clause states that no substance shown
    to cause cancer in humans or animals may be added
    to food in any amount.
  • The FDA approves food for irradiation on a
    case-by-case basis.

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