Unit 1 Spoilage and Storage.pptx

Power Point Presentation
SUBJECT CODE & NAME
20AG105PE
STORAGE AND PACKING
TECHNOLOGY
Prepared by,
Dr. P. Dineshkumar M.E., Ph.D.,
Assistant Professor,
Department of Agricultural Engineering,
Kongunadu College of Engineering and Technology.
1
Dr. P. Dineshkumar / AP / AGE / KNCET

UNITS
1. Spoilage and storage.
2. Storage methods.
3. Functions of packing materials.
4. Food packing materials and testing.
5. Special packing techniques.
2

Unit 1 – Spoilage and Storage
Food is the basic necessity of life and for healthy existence of
life of human beings.
But, Most of our food consists of agricultural and livestock
products, which are usually seasonal and spoil quickly.
Foods gradually undergo deterioration or spoilage from the
time they are harvested, caught or manufactured unless is
preserved
3

FOOD SPOILAGE
Spoilage is natural phenomenon and all foods undergo
varying degrees of deterioration or spoilage.
Spoilage may include losses in
 Organoleptic desirability.
 Nutritional value.
 Safety.
 Aesthetic appeal.
4

Spoilt: It is the term used for foods which look harmful
and unfit to eat. Spoilt food has an unattractive colour,
smell, taste and appearance.
Contamination: The term ‘Contamination’ means foods
which are not fit to be eaten for sanitary reasons. The
foods may look good, taste and smell good, but may
contain harmful chemicals, non-food matter and
bacteria.
5

The signs that food is spoiling are
1. ODOUR: “odours” are smells (sometimes like rotten eggs) that are
produced when bacteria break down the protein in food, (usually
fatty foods). This process is called putrefaction.
2. SLIMINESS: Food becomes slimy as the bacterial population
grows.
3. DISCOLOURATION: Foods can become discoloured by microbial
growth -black pin mould on bread.
4. SOURING: Foods go sour when certain bacteria produce acids. A
common example is when milk sours from the production of lactic
acid.
5. GAS: Bacteria and Yeasts often produce gaseous by-products that
can affect food. It may be noticed that meat becoming spongy, or
packages and cans swelling or having a popping or fizzing sound on
opening.
6

Food spoilage refers to the process of food
becoming unsafe or undesirable to consume,
due to the growth of microorganisms, such as
bacteria or fungi and foreign materials which
degrades its physical or chemical properties.
Categories of food spoilages
Microbial spoilage Non Microbial
spoilage
(Microorganisms) (Foreign material) 7

Microbial spoilage is the major cause of food spoilage
8
Microorganisms per gram
of food
Shelf life
100 12 Days
5000 7 Days

Undesirable changes in food due to
spoilage
Change in colour:
The fruits like bananas and apples turn black after storing for a long period of time
and reduce the acceptability of food.
Change in smell:
Rancid smell of spoiled oils and fats, bitter smell of curd or sour smell of
starchy food.
Change in consistency:
Splitting of milk, curdling of milk, stickiness and undesirable viscosity in
spoiled cooked dal and curries and spoiled cooked vegetables.
Change in texture:
Some vegetables like potato, brinjal and carrot undergo too much softening
leading to rotting.
Change due to mechanical damage:
Mechanical damages such as eggs with broken shells, mechanical spoilage
of fruits and vegetables during transportation also constitute food spoilage. 9

Classification of food spoilage on basis of
their shelf life
Non Perishable
Foods
Semi Perishable
Foods
Perishable Foods
Stays good up to an
year
Stays good for a week
to months
Spoil within a
couple of days
Eg: Sugar, Oil, Pickles etc.., Eg; Onion, Potatoes, etc., Eg. Milk, Fruits,
Vegetables etc.,
Store in a cool and dry
place
Sore in a ventilated
cool room or fridge
Store only in cold
temperature
10

Factors affecting food spoilage
11
Food
Deterioration
Reaction with
oxygen and /
or light
Time
Physical
stress
Gain or loss
of moisture
Inappropriate
temperatures
Microorganisms Food enzymes &
Chemical reaction
Insects, Parasites
and rodents

CAUSES OF FOOD SPOILAGE
 Physical causes.
 Chemical causes.
 Biological causes.
Physical causes:
Physical spoilage is caused by improper temperature,
compact stacking which leads to change in the
structure of the food.
12

Chemical causes:
The changes are brought about by enzymes present in
food (intrinsic) or those produced by microorganisms
(extrinsic) are of different kinds.
Oxidizing: enzymes destroy vitamin C and produce
deterioration in flavour.
Proteolytic: enzymes produce decomposition of proteins
like meat, fish, eggs and milk.
Amylolytic: enzymes hydrolyse carbohydrates.
Lipolytic: enzymes produce a break-down of fats into fatty
acids and glycerol that are often oxidized to peroxides and
aldehydes associated with rancidity or a bitter taste in fatty
foods.
13

Biological causes:
Biological factors that spoil food are the microorganisms
like moulds, yeasts, bacteria and their enzymes which
settle in food at different stages. The changes brought
about in the food are mainly in the form of,
 Fermentation
 Putrefaction.
14

Putrefaction
Putrefaction refers to the decomposition of organic matter,
particularly proteins, by the action of bacteria and other
microorganisms. It is characterized by the release of foul-
smelling gases and the breakdown of proteins into simpler
compounds, such as ammonia and sulphides.
15
Putrefaction
Decomposition of proteins,
by the action of bacteria
and other microorganisms
Ammonia Sulphides

Fermentation
Fermentation is a metabolic process in which
microorganisms, such as bacteria or yeast, convert
carbohydrates (such as sugars or starches) into simpler
substances, typically in the absence of oxygen. This process
involves the breakdown of sugars into alcohol, acids, or
gases, producing energy and generating various flavours,
textures, and preservation properties in foods.
16
Carbohydrates
Microorganism
s
in the absence
of oxygen
Acid Alcohol

The major types of spoilage that occur in foods are due to
microbiological, biochemical, physical and chemical
changes. These include:
 Growth and activity of microorganisms such as bacteria
and fungi.
 Gain or loss of moisture.
 Activities of food enzymes, present in all raw foods,
promote chemical reactions within the food affecting
especially the food colour, texture and flavour.
 Physical stress or abuse.
 Damage due to pests, insects and rodents etc.
17

STORAGE
Storage is an important marketing function, which
involves holding and preserving goods from the time they
are produced until they are needed for consumption.
Storage is the art of keeping the quality of agricultural
materials and preventing them from deterioration for
specific period of time, beyond their normal shelf life.
Example: Crop storage is an important aspect of post-
harvest technology
18

Necessity of Storage
 The storage of goods, therefore, from the time of
production to the time of consumption, ensures a
continuous flow of goods in the market.
 It helps in the stabilization of prices by adjusting demand
and supply.
 Storage provides employment and income through price
advantages.
 Preservation of nutritional quality.
 Opportunity for export market.
19

NATURE IN RELATION TO STORAGE
 Living organism
 Moisture rich
 Ripening process
 Bio – degradable
 Hygroscopic: Shrinkage and Swelling occur.
20

STORAGE LOSSES
Losses during post harvest operations due to
improper storage and handling are enormous and can
range from 10-40 percent. Post harvest losses can
occur in the field, in packing areas, in storage, during
transportation and in the wholesale and retail
markets. Severe losses occur because of poor
facilities, lack of know-how, poor management,
market dysfunction or simply the carelessness of
farmers. Losses can be reduced if proper storage
process is adopted after harvesting.
21

DAMAGES DURING STORAGE
Insect/ pests form one of the most important factors
responsible for losses in agricultural production at
various stages. Living organisms and the environment
interact to bring about spoilage of stored products. Living
organisms may be plants, insects, pests, man, animal,
bacteria, fungi etc.
 It is estimated that 5 to 10% of the world food
production is damaged by insects during storage.
 The estimated losses due to insects in India have been
estimated to be around 3% of the country’s production.22

Classification of damages
 Direct damages of perishable and durable
commodities
 Indirect damages of perishable and durable
commodities
23

DIRECT DAMAGES OF PERISHABLE & DURABLE
COMMODITIES
These are the damages caused by pests, insects, etc.
 Few insects consume grains as well as some
endosperm and the others eat away both. It causes in
loss of weight, loss of nutrients and loss in gradation
and consequently falls in market value.
 The contamination may be with the dead bodies, cast
skin, odour.
 Structures and containers also get damaged by causing
tunnelling in wooden parts. 24

INDIRECT DAMAGES OF PERISHABLE AND
DURABLE COMMODITIES
This includes the damage that is inflicted by consuming
infected grains. Such consumption can cause food
poisoning and various worm infections in humans.
 It may create heating and migration of moisture.
 It may create distribution of parasites to man. Certain
tape worms use stored grain insects as intermediate
hosts.
 It causes customers resistance/repulsion which may
lower the prestige.
25

FACTORS AFFECTING THE FOOD
26

Relative Humidity
Transpiration rates are determined by the moisture
content of the air, which is usually expressed as relative
humidity.
 At high relative humidity, produce maintains saleable
weight appearance, nutritional quality and flavour.
 While wilting (low relative humidity), softening the
juiciness are reduced
27

Relative humidity needs to be monitored and controlled in
storage. Control can be achieved by a variety of methods:
 Operating a humidifier in the storage area.
 Regulating air movement and ventilation in relation to
storage room load.
 Maintaining refrigeration coil temperature within the storage
room.
 Using moisture barriers in the insulation of the storage room
or transport vehicle.
 Wetting the storage room floor.
 Using crushed ice to pack produce for shipment.
 Sprinkling leafy vegetables, cool-season root vegetables
and immature fruits and vegetables with water.
28

Temperature
Respiration and metabolic rates are directly related to
room temperatures within a given range. The higher
the rate of respiration, the faster the produce
deteriorates. Lower temperatures reduce respiration
rates, which prolong the storage life of fruits and
vegetables. Low temperatures also slow the growth of
pathogenic fungi
29

Gas atmosphere
The presence and concentration of gases in the
environment surrounding the food have a considerable
influence on the growth of microorganisms, and the
atmosphere inside the package is often modified.
 The simplest way of modifying the atmosphere is
vacuum packaging, that is, removal of air (and thus O2)
from a package prior to sealing; it can have a beneficial
effect by preventing the growth of aerobic
microorganisms.
 Flushing the inside of the package with a gas such as
CO2 or N2 before sealing is the basis of modified
atmosphere packaging (MAP). 30

Light
Many deteriorative changes in the nutritional quality of
foods are initiated or accelerated by light. Light is,
essentially, an electromagnetic vibration in the
wavelength range between 4000 and 7000 A.
The intensity of light are significant factors in the
production of discoloration and flavor defects in
packaged foods.
31

Freezing injury
Temperatures that are too low can be just as damaging as
those too high. Freezing will occur in all commodities
below 0o C. Whether injury occurs depends on the
commodity.
 Injury from freezing temperatures can appear in plant
tissues as loss of rigidity and becomes softening.
 Injury can be reduced if the produce is allowed to warm
up slowly to optimum storage temperatures.
32

CONTROL MEASURES OF FOOD
DAMAGES
33

34
Control measures
Preventive measures Curative measures
Sanitation and Handling of grains
Dis-infestation of stores /
receptacles
Physical
control
measures
Mechanical
control
measures
Use of plant
products
Management of
stored product
pests in
warehouses
Fumigation
Use of low and high
temperatures
Mixing of inert dust
Activated clay
Irradiation
Use of controlled atmosphere

Sanitation and Handling of grains
 Remove dirt, debris, mud balls, foreign particles, insects
and infested grains from healthy grains that will reduce
insect infestation.
 Bags should be stacked on wooden dunnage 0.5 metre
away from the wall.
 Sun drying and use of mechanical dryers can be opted
to bring down moisture.
 Impregnation of gunny bags with insecticides can
prevent entry of insects.
 Polythene lined gunny bags were suggested for
storage. 35

Dis-infestation of stores / receptacles
 Treatment of bulk and bag storage structures with
insecticides is an important practice to avoid latent
infestation in reused bags and bulk storage
structure.
 Plant Quarantine Order 2003, govern the regulation
or restriction of movement of insects through
commodities into the country and among different
areas within the country.
 Grains or other commodities are thoroughly checked
and treated at ports to avoid entry of insects.
36

Physical control measures
1. Use of low and high temperatures: The insects can be controlled
either by increasing or decreasing storage temperatures.
◦ Optimal temperature for most of the storage insects is between 25 ℃ and 33 ℃.
◦ At low temperature (13 ℃ - 25 ℃) – Slow development
◦ High temperatures of 35 ℃ and above - Stop development
2. Mixing of inert dust:
◦ 1st Group - Consists of clays, sand, paddy husk ash, volcanic ash and wood ash.
◦ 2nd Group - Consists of a great number of minerals such as dolomite, rock
phosphate, ground sulfur, lime limestone and common salt.
◦ 3rd Group - Consists of dusts that contain synthetic silica (silicon dioxide).
◦ 4thGroup - Consists of dusts that contain natural silica, such as diatomaceous
earth (DE).
37

3. Activated clay:
◦ Activated clay (kaolin) has been used in protecting grains from the attack of
storage insects.
◦ This method is very effective against most of the storage pests and nontoxic to
higher animals.
4. Irradiation:
◦ Low dose irradiation completely kills or sterilizes the common grain pests, and
even the eggs deposited inside the grains.
◦ Ideally suited for large-scale operations, thereby offering substantial economic
benefits.
5. Use of controlled atmosphere:
◦ The normal storage atmosphere (or earth’s atmosphere) contains 78% Nitrogen
(N2), 21% Oxygen (O2) and 0.03% carbon dioxide (CO2).
◦ In grain storage, insects can be controlled by decreasing O2 or increasing CO2 or
N2 concentration in the atmosphere thereby interfering with the normal respiration
of insects.
38

Mechanical control measures
Several mechanical devices have been developed both for
monitoring and mass trapping stored product insects.
 Entoleters: The material is fed to the center of a high-speed
rotating disc carrying studs so that it is thrown against the studs
the impact kills insects and destroys their eggs.
 Other traps: Probe trap, Pulse Beetle Trap, Light traps, Sticky
traps, Bait traps, Pheromone traps
39

Use of plant products
 Neem leaf powder, Nochi leaf powder, turmeric powder,
Sweet Flag (Vasambu) all at 10g /kg have been found to
be effective against storage pests.
 Experimental results show that the fresh leaves of Nochi
mixed with paddy at the rate of 2% w/w protected the
grains from insect attack for 9 months.
 Garlic extract is yet another plant product which is
nontoxic and was found to be grain protectant.
40

Management of stored product pests in
warehouses
 Maintain store house hygiene brushing the cracks, crevices
and corners, removing all debris and cleaning the entire
godown before storing the grains.
 Reduce moisture content below 10 %.
 Dry all the bags, bins etc in the sun.
 Eliminate conditions which favour storage pests sieving and
removing all broken grains, stitching all torn bags before
filling.
 Apply stack spraying over the bags.
Ex: Malathion50 EC (widely used in for Controlling Flies Mosquitoes
Cockroaches, bedbugs , ants flies , household insects).
41

Fumigation
 Decide the need for shed fumigation (entire store house or
godown) or cover fumigation.
 Insert the required number of aluminium phosphide tablets in
between the bags in different layers.
 Aluminium Phosphide For cover fumigation: 3 tablets of 3 g
each per tonne of grain. (Atmospheric moisture in the burrow
activates aluminum phosphide to produce hydrogen
phosphide.)
 Period of fumigation: 5 days
42

43
Types / Classification of storage
Duration of storage Size or Scale of storage Principle of storage
Short term storage
Medium term storage
Long term storage
Small scale storage
Medium scale storage
Large scale storage
Physical storage
Chemical storage
Biological storage

Classification based on duration of storage
Short Term Storage: Stored products in short term storage mostly do not
last beyond 6 months. Highly perishable products (such as egg, meat, fish
and dairy products) are naturally stored for short term.
Medium Term Storage: Medium term storage involves keeping the
quality of stored products without appreciable deteriorations for up to 12
months. The quality of such stored products may not be guaranteed after
18 months.
Long Term Storage: Long term storage can guarantee the quality of
stored products beyond 5 years. Germ banks and some storage systems
are known to preserve viability and proximate characteristics of stored
materials for decades.
44

Classification based on scale of storage
Small Scale Storage: Small scale storage systems have capacity for
up to 1 ton, but not beyond. They are mostly used at domestic and
peasant levels. They are associated with peasant farmers with small
farm holdings.
Medium Scale Storage: Medium scale storage can accommodate
up to a hundred tons of stored products. Most of such storage
systems are in the capacity range of 2 – 50 tons, with very few
having capacity beyond 50 tons.
Large Scale Storage: Large scale storage can accommodated stored
material in 100s and1000s of tons. It is used either for temporary or
permanent storage of very large quantity of various products. It has a
very high initial cost.
45

Classification based on principle of storage
Physical Storage: Physical storage utilizes physical principles to achieve
storage and preservation the quality of stored products. The physical
environment in terms of moisture content, temperature and relative
humidity.
Chemical Storage: Chemical storage utilizes chemicals to stop or retard
the activities of agents of deterioration. The use of chemicals such as
wax, dust or tablet to prevent respiration of insect.
Biological Storage: Biological storage utilizes biological agents,
especially microorganism, to stop or retard the activities of agents of
deterioration or enhance the shelf life of stored products. 46

47
Factors affecting losses in storage
Mechanical and
Environmental
Infestation
Biochemical
Processes
1. Handling damage
2. Handling spillage
3. Moisture stresses and movements
1. Bacteria, Molds, and fungi
2. Insects
3. Rodents
4. Birds
1. Vitamin losses
2. Fat acidity
3. Natural respiration

TYPES OF STORAGE LOSSES
48

49
TYPES OF STORAGE LOSSES
Quantitative loss Qualitative loss Commercial Loss
Weight Loss Loss in quality
Nutritional loss
Loss of seed viability
Monetary loss
Loss of goodwill
Loss due to legal
action

Quantitative loss: Quantitative loss is a physical loss of substance. It is
the form of loss that can most readily be measured and valued.
Weight Loss: Losses due to reduction of weight or volume.
• Moisture changes may lead to an increase in weight and in some cases
production of water by and insect infestation may partly offset the
weight loss
• Direct feeding insects cause loss in weight of the stored grains.
• A rice weevil will eat 14 mg out of 20 mg of a rice kernel.
50

Qualitative loss: is more difficult to assess and is perhaps best
identified through comparison with well-defined standards.
1. Loss in quality:
◦ Generally quality is assessed and products graded on the basis
of appearance, shape, size, etc.,
◦ Chemical changes may also be important, e.g. in oilseeds.
Infestation in groundnuts may cause an increase in the free
fatty acid level leading to rancidity in the oil.
51

2. Nutritional loss:
◦ Rodents and moth larvae may preferentially attack the germ
of the grain thus removing a large percentage of the protein
and vitamin content, whereas weevils feeding mainly on the
endosperm will reduce the carbohydrate content.
52

3. Loss of seed viability
◦ Seed grain is usually more carefully stored owing to its
greater potential value. Loss may be caused by changes of
light, temperature, moisture, excessive respiration, infestation
and, in some cases, the methods used to control infestation.
Direct feeding on the grain.
Chemical changes in grain content.
Contamination of grains with moult skin and body parts.
Spreading the pathogenic micro-organisms.
Loss of seed viability.
Insects were found to cause the loss of viability of seeds to
an extent of 3.6 to 41 % in paddy.
53

3. Commercial Loss
Commercial losses may be a consequence of any of the
foregoing factors or be the preventive or remedial actions
required, as well as equipment costs. These losses are
generally incurred through a lack of knowledge,
experience or managerial ability.
1. Monetary loss
Losses in packaging and the costs of repacking due to
rodent and handling damage, repairs and stoppages in
machinery, damage to the fabric of the store are all
economic losses
54

2. Loss of goodwill
This is not directly accountable but nonetheless it is
very important, especially with regard to rising quality
standards. This is particularly so in exports where a
reputation for high quality produces is valuable to a
country's economy.
3. Loss due to legal action
This may include damages awarded due to
impairment of health of humans and animals, expenses
incurred by third persons due to infestation traceable to a
particular shipment, and various actions due to
55

ESTIMATION OF LOSSES
 Weeviled and Germ Eaten Grain Counting Method
 Comparing Healthy Grains and Damaged Grains
 Counting and Weighing Method (Gravimetric Method)
 Converted Percentage Damage Method
56

Weeviled and Germ Eaten Grain Counting
Method
The insects such as rice germ eaten and rice weevil,
eat out the contents of the grain from within and result
into Weeviled grains.
57

Procedure
1. Grain sample of 50 g is taken.
2. From which a random sample of 100 grains is drawn.
3. Out of these 100 grains, Weeviled grains and germ eaten
grains are sorted out and are separated from the samples.
4. Are counted separately.
5. The 100 more purely health grains are randomly selected and
weighed.
58

Calculation
Where,
W = Percentage by number of Weeviled grains.
G = Percentage by number of germ eaten grains.
W1 = mass of W grains (in grams).
G1 = mass of G grains (in grams).
S = mass of 100 healthy grains (in grams).
59
Mass Loss (%) = (W+G) – 100/S (W1 + G1)

 This method lays stress on the nature of the damage.
 This method first involves,
The separate counting of two types of damaged grains.
And then again counting a separate set of hundred healthy grains
for ultimately arriving at mass loss due to insect pests.
 This method, hence, is preferred where pest complex
causing the different nature of damages is causing
infestation to the grains.
60

Comparing Healthy Grains and Damaged
Grains
Procedure
 In this method, a random sample of 50 g of grains is taken.
 Out of which hundred grains are randomly selected.
 Out of these hundred grains, the number of damaged grains
are separated and counted and the same are then weighed.
 Then an equal number of healthy grains are selected and
counted
 One more separate set of hundred exclusively healthy grains
is selected and weighed.
61

Calculation
Where,
➢ n1 = mass of the number of damaged grains in 100 grains (in grams).
➢ n = mass of the equal number of healthy grains (in grams).
➢ n2 = mass of 100 healthy grains (in grams).
62
  1
2
% 100
n n
Mass Loss X
n
 

  
 

 Under this method, the damaged grains are put in a single lot
irrespective of the nature of the damage inflicted by insect
pests.
 This method is quite time consuming since
It involves three sets of grains and counting of an equal number of
times as first the damaged grains have to be counted.
63

Counting and Weighing Method (Gravimetric
Method)
 The most common method and has been widely adopted
throughout the world
 Since this is a very easy method that employs only one set of
grains
 Wherein only two counting and weighing is sufficient to
reach at mass-loss.
64

Procedure:
 Generally, a sample size of 100 to 1000 grains for this method
is recommended.
 However, some has set a limit of 1000 grains.
 Out of this sample, the damaged and undamaged grains are
sorted out and are then counted and weighed.
65

Calculation:
Where,
U = Mass of undamaged grains (in grams).
Nu = Number of undamaged grains (in grams).
D = Mass of damaged grains (in grams).
Nd = Number of damaged grains (in grams).
66
 
   
 
* *
% 100
d u
d u
U N D N
Mass Loss X
U N N
 

  
 

 

Besides the simplicity of this method, it has advantage that
 Damage by different species of insects causing different type of nature
of damages can also be estimated.
 Under such case, out of the damaged grains, the grains infested by a
particular species of insect-pest are separated.
 Counted and weighed separately
 Then per cent mass loss due to that particular insect can be worked out.
 This method has wide acceptance since it can also be used to determine
damage caused by termites, rodents and birds.
67

Converted Percentage Damage Method
Though this method is very quick and does not involve
much equipment, it is not very accurate method, it may,
however, be recommenced rather than guessing.
68

Procedure
 Take a random sample of 100 to 1000 grains
 Count the number of bored grains in the above sample
 Calculate the percentage of bored grains
69

Calculation
70

Equipment’s used for estimation of
losses
 Seed counter
 Weighing balance
 Polythene sample bags
 Liquid fumigant such as CCl4 to retain sample for
examination at a later date.
 Sieve of suitable size for removal of insects, dusts and
any prior processing.
71

Unit 1 Spoilage and Storage.pptx

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