Thermal Preservation
Definition

Adding or removing heat to alter shelflife. Shelf-life -- time food can be
stored and still maintain its quality


Heat processing -- adding heat to a food
to destroy enzymes and some spoilage
and pathogenic bacteria.
Cold processing -- removing heat from
food to slow deterioration from enzymes
and bacteria.
D 9.01 -- Thermal Preservation
Types of Thermal Preservation

Heat processing
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Blanching
Commercial sterilization
Pasteurization
Sterilization
Dehydration
Canning
Cold processing


Refrigeration
Freezing
D 9.01 -- Thermal Preservation
Blanching



Immersing food in
boiling water or steam
to destroy enzymes.
Often used before
freezing or drying
foods.
Product shelf-life is
short.
D 9.01 -- Thermal Preservation
Commercial Sterilization


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Combines heat and
vacuum seal to destroy
spoilage and pathogenic
microorganisms.
Product shelf-life is long.
Examples include water
bath, retort, or
hydrostatic cooker and
cooler
D 9.01 -- Thermal Preservation
Pasteurization



A low heat treatment
that destroys pathogenic
microorganisms and
stops enzyme activity
Products have a medium
shelf-life.
Examples include batch,
high temperature, and
short-time.
D 9.01 -- Thermal Preservation
Sterilization



A high temperature
heat treatment that
destroys all
microorganisms.
Products have a
long shelf-life.
Examples include
aseptic canning.
D 9.01 -- Thermal Preservation
Dehydration


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Low temperature heat
treatment that involves the
removal of water as a means
to prevent microbial growth.
Products have a long shelflife.
Examples include tray, belt,
drum, spray, vacuum, freezedrying, sun, and oven drying
D 9.01 -- Thermal Preservation
Concentration



Removal of a portion of
water from food to
prevent microbial growth.
Products have a medium
shelf-life.
Examples -- open kettle,
heat evaporation, vacuum
evaporation, and filtration
D 9.01 -- Thermal Preservation
Refrigeration


Slows enzyme activity
and microbial growth.
Products have a short
shelf-life.
D 9.01 -- Thermal Preservation
Freezing


Slows enzyme
activity and
microbial growth
Products have a
long shelf-life
D 9.01 -- Thermal Preservation
Non-Thermal Preservation
Definition


Involves manipulating the properties
of food or its environment without
using heat.
Examples include:




Irradiation
Ohmic heating
Ozonation
High pressure processing
D 9.01 -- Thermal Preservation
Irradiation


Exposure of food to
ionizing radiation for
preservation
In the U.S.
irradiated foods are
required to be
labeled.
D 9.01 -- Thermal Preservation
Ohmic Heating

Food is subjected to
an alternating
current flow between
two electrodes.
D 9.01 -- Thermal Preservation
Ozonation

Water treatment
process used to
destroy
microorganisms by
ozone, a gas
produced by exposure
of oxygen molecules
to high electric
voltage
D 9.01 -- Thermal Preservation
High Pressure Processing

Preservation method
where liquid and solid
foods are subjected to
pressures of 45,000
pounds per square
inch or higher.
D 9.01 -- Thermal Preservation
Tamper-evident Devices
D 9.01 -- Thermal Preservation
Definition


A package that has “one or more indicators or
barriers to entry which, if breached or missing,
can reasonably be expected to provide visible
evidence that tampering has occurred.”
Packages are made so they cannot be
duplicated with commonly available materials
or through commonly available processes.
D 9.01 -- Thermal Preservation
Other considerations

The visual indication should be
accompanied by a precautionary
label.


describing the tamper-evident feature(s)
and
warning that absence of or damage to such
feature(s) at time of purchase is a sign of
possible tampering.
D 9.01 -- Thermal Preservation
Many different types



There are many types of tamperevident devices.
Research and development is on-going
to make these devices more secure.
Examples will be shown.
D 9.01 -- Thermal Preservation
Food Packaging
D 9.01 -- Thermal Preservation
What is food packaging?

Enclosing food to protect food from
tampering or contamination from



physical,
chemical, or
biological sources.
D 9.01 -- Thermal Preservation
Six Functions of Packaging
1.
2.
3.
4.
5.
6.
Barrier between food and contaminants.
Protects food from impact during shipping and
storage.
Acts as a dispenser
Protects food from moisture, gas, odors, and
light
Identifies the contents
Serves as a cooking and storage container.
D 9.01 -- Thermal Preservation
Food Packaging Materials

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Metals (steel, tin, and aluminum) -- canned foods
Glass -- beverages, pickles, condiments
Paper (usually coated with wax, plastics, or
aluminum foil) -- cartons of milk, crackers
Plastics -- milk jugs, beverages, deli salads
Packaging films (cellophane, edible films, and
coatings) -- candy bars, hot dog casings, chips
Laminates (layering materials into one product) -drink boxes
D 9.01 -- Thermal Preservation
Packaging Types
Food package
Food
Aseptic packaging
Liquid whole eggs
Bags
Potato chips
Boxes
Box of cereal
Cans
Can of soup
Cartons
Carton of eggs
Flexible packaging
Bagged salad
Wrappers
Used to cover a package.
D-9.02
Food
Packaging
D-9.02
Food
Packaging
Reduced oxygen packaging



Some packaging methods involve changing the
environment that surrounds food to increase
the shelf life.
Reduced oxygen packaging (ROP) provides an
atmosphere that has little or no oxygen in the
environment surround the food.
Three types of ROP are:



Controlled atmosphere packaging
Modified atmosphere packaging
Vacuum packaging
D 9.01 -- Thermal Preservation
Controlled Atmosphere
Packaging


Controls the movement
of gases inside the
package.
Used with:

fresh-cut salads.
D 9.01 -- Thermal Preservation
Modified Atmosphere Packaging


Flush the food
container with a gas,
CO2 or N2., before the
container is sealed
Use with:


potato chips and other
snack foods
fresh pasta
D 9.01 -- Thermal Preservation
Vacuum Packaging


Remove all air,
including oxygen, from
inside the packaging
environment.
Used with:



Country ham slices,
deli meats,
bacon
D 9.01 -- Thermal Preservation
Determination of what type of
package to use

The type of packaging material used with
a specific food product depends on:




the function the package must perform
the protection needed
conditions of shipping and storage
chemical composition of the food
D 9.01 -- Thermal Preservation
Food Packaging
D 9.01 -- Thermal Preservation
What is food packaging?

Enclosing food to protect food from
tampering or contamination from



physical,
chemical, or
biological sources.
D 9.01 -- Thermal Preservation
Six Functions of Packaging
1.
2.
3.
4.
5.
6.
Barrier between food and contaminants.
Protects food from impact during shipping and
storage.
Acts as a dispenser
Protects food from moisture, gas, odors, and
light
Identifies the contents
Serves as a cooking and storage container.
D 9.01 -- Thermal Preservation
Food Packaging Materials






Metals (steel, tin, and aluminum) -- canned foods
Glass -- beverages, pickles, condiments
Paper (usually coated with wax, plastics, or
aluminum foil) -- cartons of milk, crackers
Plastics -- milk jugs, beverages, deli salads
Packaging films (cellophane, edible films, and
coatings) -- candy bars, hot dog casings, chips
Laminates (layering materials into one product) -drink boxes
D 9.01 -- Thermal Preservation
Packaging Types
Food package
Food
Aseptic packaging
Liquid whole eggs
Bags
Potato chips
Boxes
Box of cereal
Cans
Can of soup
Cartons
Carton of eggs
Flexible packaging
Bagged salad
Wrappers
Used to cover a package.
D-9.02
Food
Packaging
D-9.02
Food
Packaging
Reduced oxygen packaging



Some packaging methods involve changing the
environment that surrounds food to increase
the shelf life.
Reduced oxygen packaging (ROP) provides an
atmosphere that has little or no oxygen in the
environment surround the food.
Three types of ROP are:



Controlled atmosphere packaging
Modified atmosphere packaging
Vacuum packaging
D 9.01 -- Thermal Preservation
Controlled Atmosphere
Packaging


Controls the movement
of gases inside the
package.
Used with:

fresh-cut salads.
D 9.01 -- Thermal Preservation
Modified Atmosphere Packaging


Flush the food
container with a gas,
CO2 or N2., before the
container is sealed
Use with:


potato chips and other
snack foods
fresh pasta
D 9.01 -- Thermal Preservation
Vacuum Packaging


Remove all air,
including oxygen, from
inside the packaging
environment.
Used with:



Country ham slices,
deli meats,
bacon
D 9.01 -- Thermal Preservation
Determination of what type of
package to use

The type of packaging material used with
a specific food product depends on:




the function the package must perform
the protection needed
conditions of shipping and storage
chemical composition of the food
D 9.01 -- Thermal Preservation