Food preservation is the process of preventing spoilage in foods like fruits and vegetables while maintaining their color, taste, and nutritive value. Common techniques include drying, smoking, salting, canning, and refrigeration, each effective at inhibiting microorganism growth. Preservation methods vary from cold preservation, which slows reactions to extend shelf life, to heat preservation, which uses processes like pasteurization to eliminate harmful organisms.

1. Food Preservation METHOD

2. What is Food Preservation
A process by which certain foods like fruits and vegetables are
prevented from getting spoilt for a long period of time. The
colour, taste and nutritive value of the food is also preserved.
When you keep fruits, vegetables or left over dal in the
refrigerator or in a cool place, will this be called food
preservation? No, because you can store fruits and vegetables
or left over dal in this state for a few days only
The definition of food preservation states that the preserved
food should retain their colour and taste. This means that the
colour and taste of food which is present at the time of
preservation should not change

3. Preserving food involves creating environments
that microorganisms do not like.
*Preservation Techniques:
1. Drying
2. Smoking
3. Salting
4. Pickling
5. Canning
6. Cold Temperatures

4. Food Preservation Methods
 Drying is the food
preservation process
that consists of
removing the food’s
water, which
effectively inhibits the
growth of
microorganisms. Like:
 Sun Drying

5. Food Preservation Methods
Commercial Drying
 The most important types of commercial
drying are:
Conventional: heat.
Vacuum: pulls the water out.
Osmotic: water drawn out by osmosis.
Freeze-drying: ice crystals vaporize.

6. Food Preservation Methods
Sublimation: The process in which a solid changes
directly to a vapor without passing through the liquid
phase.

7. Food Preservation Methods
 Cure: To preserve food through the use of salt
and drying. Sugar, spices, or nitrates may also
be added.
 Fermentation
 Pickling uses vinegar to preserve foods.
 Edible coating: Thin layer of edible material
such as natural wax, oil, petroleum-based wax,
etc. that serves as a barrier to gas and moisture.

8. Food Preservation Methods
 Canning is a two-step process:
 First the food is prepared by being packed into
containers, which are then sealed.
 Then the containers are “canned,” or heated to
ensure that all microorganisms are destroyed.
 Sterilization: The elimination of all microorganisms
through extended boiling/heating to temperatures much
higher than boiling or through the use of certain
chemicals.

9. Cold Preservation
 Refrigeration slows down the biological,
chemical, and physical reactions that shorten
the shelf life of food.
 For safety purposes, refrigerators should be kept
between just above freezing to no more than
40°F (4°C).
 All perishable foods should be refrigerated as
soon as possible, preferably during transport, to
prevent bacteria from multiplying.

10. Cold Preservation
 Freezing makes water unavailable to
microorganisms.
 The chemical and physical reactions leading to
deterioration are slowed by freezing.
 Rancid: The breakdown of the polyunsaturated
fatty acids in fats that results in disagreeable
odors and flavors.
 Freezer burn: White or grayish patches on
frozen food caused by water evaporating into the
package’s air spaces.

11. Heat Preservation
 Pasteurization: A food
preservation process that
heats liquids to 160°F
(71°C) for 15 seconds, or
143°F (62°C) for 30
minutes, in order to kill
bacteria, yeasts, and
molds.

12. Thank youThank you
presented by saurabh bansal B.tech ECE 3rd
sem 04/25/15