Food spoilage occurs when microorganisms like bacteria, molds, and yeasts cause foods to deteriorate and become inedible. The main factors that determine spoilage are water activity, temperature, pH, and atmosphere. Different foods spoil in different ways due to their properties - for example, molds are more likely than bacteria to cause fruit and vegetable spoilage. Food preservation methods like boiling, refrigeration, and canning aim to stop microbial growth and slow spoilage. Properly preserving foods maintains nutritional value and protects consumers from food poisoning.

1. PRESENTED BY
Amor Jyoti Borah (16/BBT/02)
K.Bishal Singha (16/BBT/10)
Mirangka Terangpi (16/BBT/37)

2. What is spoilage ?
Types of spoilage
Factors determining the spoilage
Spoilages of different items :
A) Fruit And Vegetable Spoilage
B) Milk Spoilage
C) Cereal Spoilage
D) Fish/Meat Spoilage
Prevention of food Spoilage
Why should foods be preserved ?
Conclusion
References

3. WHAT IS FOOD SPOILAGE ?
Food spoilage can be defined as:
• any changes in the visual, smell and texture of food
that makes it unacceptable for consumption.
OR
• is the process in which food deteriorates to the
points it is not edible to humans or its quality of
edibility becomes reduced.

4. SIGNS OF SPOILAGE
 Odor:
– Breakdown of proteins
e.g. “rotten egg” smell
 Sliminess
 Discoloration
– Mold on bread, blue and green mold
on citrus fruit and cheese.
 Souring
– Production of acid
e.g. sour milk from production of lactic acid
 Gas formation
– Meat becomes spongy
– Swollen or bubbling packages and cans.

5. TYPES OF SPOILAGES
Two types of Spoilage:
• Microbial Spoilage
• Non- Microbial Spoilage
Microbial Spoilage :
This refers to damage to food that is caused by
micro organisms (bacteria, moulds and yeasts). Micro
organisms can grow in almost all kinds of food products

6. Non microbial spoilages :
This can be referred those changes in food which is not
caused by the microbes. It involves some other factors for food
spoilages.
They can again be categorised as - Physical spoilage and
Chemical spoilages.
Physical spoilages :
- Indicated by moisture loss or gain.
Chemical Spoilages :
- Browing of fruits and vegetables.

7. Classification of food by ease of Spoilage
Foods can be classified into three groups based on
ease of spoilage:
I. Stable or non perishable foods :
Foods which do not spoil unless handle carelessly.
Examples: Sugar, flour and dry beans.

8. II. Semi perishable foods :
If these foods are properly handled and
stored, they will remain unspoiled for a fairly long
period.
Examples: Potatoes, Apples and Nuts.

9. III. Perishable foods :
This group includes most of our important daily
foods that spoil readily unless special preservative
methods are used.
Examples: Meats, Fish, Milk, Vegetables, Eggs etc.

10. FACTORS DETERMINING SPOILAGES
 Water activity
 Temperature
 Environment where foods are Stored
 pH
 Atmosphere Conditions
 Humidity

11. FRUIT AND VEGETABLE SPOILAGE
 In vegetables where bacterial growth is not favored (e.g. low pH),
molds are the principal spoilage agents.
 Because bacteria grow more rapidly, they usually outcompete
fungi for readily available substrates in vegetables.
 As a result, bacteria are of greater consequence in the spoilage of
vegetables with essential properties that support bacterial growth
(favorable pH).
 The pH of fruits does not favor bacterial growth. As a result,
yeasts and molds are more important than bacteria in the
spoilage of fruits.
 Yeast often initiate fruit spoilage then molds finish the spoiling
job by degrading complex polysaccharides in cell walls.

12. MILK SPOILAGE
 Psychrotropic pseudomonads are
common microbes found in raw milk
which produces heat stable enzymes that
can reduce milk quality and shelf life.
 Pasteurization kills most yeasts and
molds.
 Milk is more frequently spoiled by aerobic spore formers such as
Bacillus, whose proteolytic enzymes cause curdling.

13. CEREAL SPOILAGE
The major factors involved in the spoilage of
grains by molds are moisture levels, physical
damage, and temperature.
The main genera of molds causing spoilage during
storage of cereal grains are Aspergillus and
Penicillium.

14. FISH AND MEAT SPOILAGE
 Meat spoilage is characterized by the
appearance of off odors and slime.
 Several molds grow on the surface of meat
and can cause spoilage like Penicillium,
Mucor, Cladosporium, Alternaria, but
cannot grow on meat stored below 5O C.
 Storage temperature is the single most
important control factor for meat spoilage.
 Fish have high nitrogen content but no
carbohydrate.
 The microbial quality of fish is heavily
influenced by the quality of the water.

15. PREVENTION OF FOOD SPOILAGE
IT CAN BE ACHIEVED BY USING THE METHOD
CALLED FOOD PRESERVATION .
 Food preservation is the process of treating and
handling food, with an aim to stop or slow down its
spoilage while maintaining its nutritional value,
texture, and flavour.
 Food preservation methods either kill microbes or
prevent their growth.

16. Some food preservation methods includes :
1. Boiling
2. Dehydration
3. Refrigeration & freezing
4. Canning
5. Using chemical preservatives
6. Using Salt, sugar, oil, or vinegar
7. Pasteurization

17. Why should foods be Preserved ?
Food preservation prevents the growth
of microorganisms (such as yeasts), or
other microorganisms.
To prevent poisoning of foods.
Some methods of food preservation are
known to create carcinogens. Example :
meat that has undergone salting, curing,
fermenting, and smoking, as carcinogenic
to humans.
Maintaining or creatingnutritional value ,
texture and flavor is an important aspect of
food preservation.

18. CONCLUSION
CONCLUSIONS THAT WE DRAW FROM FOOD SPOILAGE ARE :
 STORAGE OF FOOD IS AN IMPORTANT MATTER OF OUR CONCERN.
 TAKING OF SPOILED FOODS MAY RESULT IN FOOD POISONING. HENCE IT
MAY SOMETIMES BE THE CAUSE OF DEATH.

19. REFERENCES
o Google
o Wikipedia