3. Food Preservation
• Methods of treating foods to delay the
deterioration of the food.
• Changing raw products into more
stable forms that can be stored for
longer periods of time.
• Allows any food to be available any
time of the year in any area of the
world.
4. Why process foods?
• Extend edible time frame -Preservation
• Make better tasting foods
• Make more varieties of food
• Convenient
5. Historical Methods of Food
Preservation
Primitive and tedious methods
Drying
Salting
Sugaring
Pickling
Cold storage
6. Drying
Used to preserve fruit, vegetables,
meats, and fish.
Mainly used in the south –
warmer climate.
Extraction of moisture by sun,
air, heat or vacuum to inhibit the
growth of molds, bacteria and
yeasts
7. Salting
Used extensively for pork,
beef, and fish.
Coating food in salt or placing
it in a salt solution (brine)
reduces the moisture content
of the food, i.e. reduces the
availability of water.
With little moisture, micro-
organism growth is retarded.
8. Sugaring/ Sugar
Preserve
Used to preserve fruits for the winter.
Jams and jellies.
The initial boiling of the fruit will destroy the
enzymes and micro-organisms (but not spores),
preventing spoilage later on.
The high concentration of sugar added during
the jam making process makes the water
unavailable thus reducing the microbial activity
through dehydration effect.
10. Curing
• The addition of a chemical compound (sodium
nitrate or sodium nitrite) to food to slow the growth
of bacteria.
11. Fermentation
• The use of special bacteria, molds or yeasts to
prevent spoilage by converting the elements of food
that spoil easily to stable elements that act as
preservatives.
12. Freeze Drying
• The freezing of food and the subsequent removal of
water from the frozen food through the use of heat
and a vacuum.
13. Smoking
• The addition of smoke and heat to preserve food by
the action of the chemicals from the smoked wood
and the partial drying of the food.
17. Freezing
• The lowering of the temperature of food to
temperatures below 28 degrees F to stop the growth
of bacteria, yeasts and molds and to kill parasites.
