This presentation based on food preservation techniques and the theories that aim for food preseravation.This presentation most suitable for undergraduate students who wish to learn food science.

1. Food Preservation

2. Lesson Outline
Definition
Factors that affect the food spoilage
Aims of food preservation
Methods of Food Preservation
Food Additives
Food preservatives
Advantages and Disadvantages of food preservation
Important Information in a label of a food package

3. What is Food Preservation
“The process of making food stay longer by artificially
controlling the factors affecting food spoilage is called
food preservation’’

4. Factors that affect food spoilage
• Microorganisms
• Enzymes
• Air
• Light
• Insects, Rodents, Parasites and Other Creatures
• Physical Damage
• Temperature

5. Aims of food preservation
• Reduction of food spoilage
• Prevention of food poisoning
• Use of excess food by processing to use in off seasons
• Eg- Jak fruit- Dried Jak Fruit(Atu kos)
-Milk – Sterilized milk
-Lime – Lime pickle

6. Methods of Food Preservation
• Suppress the factors that causing food spoilage
• Preventing microorganisms getting to the food
• Controlling the temperature and water content to reduce
the microbial activity
• Prevention of damage caused by macroorganisms
• Food Preservation
1.Traditional Methods
2.Modern Methods

7. Traditional Methods
1.Salting
2.Drying
3.Smoking
4.Immersing in honey
5.Keeping under dry sand

8. Modern Methods
• Drying
• Drying by solar heat(chillies, fruits, vegetables )
• Stove drying(chillies, fruits, mushrooms)
• Spray drying(milk)

9. Freezing (4 °C) Deep freezing (-18 °C)
Suppress the growth of
microorganisms
Natural colour, taste and
nutritive value of food can be
protected to a large extent
Vegetables and fruits Meat, fish and ice cream
• Temperature control
1. Freezing
2. Deep Freezing
• Concentration(Removing Water/moisture)
canning and bottling controls the growth of microorganisms
Eg- Jam and Cordials

10. Preservation method Reducing Factor
Drying Reduce the moisture content
Control of temperature (freezing
and deep freezing)
Reduce the favorable
temperature for microorganisms
Concentration/ immersing in
honey
Remove the moisture
Smoking Minimizing microbial activity due
to chemicals in smoke and
removal of water from food
Adding chemicals (preservatives) removal of water in food
Summary

11. Food Additives
• The chemical substances added to the packaged food in
preservation are called additives

12. “The substance used to prevent the action of microorganisms causing
food spoilage and the effect of other external and internal factors are
known as preservatives”
Some chemical preservatives
• Sodium metabisulphite
• Sodium chloride
• Sodium bisulphite
• Sodium nitrite
• sodium nitrate
• Benzoic acid
• Acetic acid
Food Preservatives

13. • Fresh, ripe fruit Washing,
• Remove of skin/ seeds,
• Cutting into small pieces
Heating (3 minutes)
Add 1g of citric
acid(Lime)
Add 300g
Sugar
Heating at a high temperature
for a short period of time (100
o C - 2 minutes)
Heating again
slowly
Add 10-15 g of pectin
and
200 g of sugar
Slowly
Heating
Mixing well
Add sodium
metabisulphit
Bottling in sterilized bottles
while remaining at the same
temperature
Preparation of Jam

14. • The code (E number) is adopted by the European Union to
symbolise the food additives approved for use and are
experimentally confirmed as safe
• The preservatives from E 200 to E 299 have been allowed to add
to the food as synthetic food additives. Mainly acids and salts
can be seen among these

15. Various types of preserved food
• Use for direct consumption -Jam, Chutney,fruit drinks
• Consumed after instant preparation-Meat balls, sausages,
noodles, macaroni, coconut milk powder, cordial
• needs to be cooked before consumption-Dried fish

16. Advantages of food preservation and
processing
• Prevent food spoilage
• Ability to select according to appetite
• Ability to impart an attractive look for food
• Ability to increase the nutritional value of some food types
(yoghurt, cheese) by changing their existing nature
• Utilize the surplus effectively
• Ability to keep them for off season consumption
• Minimize the damage caused by insects and other animal

17. Disadvantages of food preservation
• Running a risk of being prone to diseases for the addition of
non permitted additives and addition beyond prescribed limits
• Increase in the risk of causing diseases due to artificial
additives such as flavours and colourings
• Possibility of destroying vitamins and other nutrients
• Tendency to change the characteristic flavour, smell and colour
of the food
• Reduce the desire for natural food and getting used to
consumption of instant food

18. Important Information in a label of a food
package
• Date of manufacture and date of expiry
• Net weight / Total weight
• Standard
• Producer (Institution / Country)
• Environment friendliness / Consumer friendliness of the
packet/ wrapper