This document discusses measures to reduce grain losses during transit and storage. It provides permissible loss limits for different transit distances and storage structures. Natural losses from respiration and dust are allowed for in storage norms. Insects and rodents are major causes of storage losses. Common storage pests include weevils and moths. Proper aeration, fumigation, and use of chemicals like malathion can control pests. Hermetic storage using sealed bags can generate modified atmospheres through respiration to naturally inhibit pests without chemicals. Aeration cools grain and slows insects while prolonging pesticide effectiveness.

1. Grain Losses and Control
Measures

2. • Grain losses occur not only in storage but also in transit
• By establishing proper norms, the transit losses can be considerably
reduced
• The maximum permissible loss in transit is 0.1% for distances up to 1000
kms, 0.15% for distances up to 2,000 kms and 0.20% for distances over
2000 kms
• As to losses in storage, the norms developed relate to only natural losses of
grain and grain products
• This would mean losses resulting from respiratory properties of the grain
and also due to loss of fine dust in the grain
• There is also allowance made for losses resulting from rodents, insects, etc

3. • The permissible loss for wheat, rye and barley stored in bulk in flat warehouses
over one year, for example, is 0.12% and if stored in grain elevators 0.10%.
Equivalent figures for paddy are 0.15% and 0.12%.
• Insects and rats are the greatest enemy of human being in so far as the loss of
food grain are concern
• Some of the well known insect causing damage to the stored grain are Rice
weevil, Khapra beetle, Pulse beetle, Rice moth, Grain moth etc
• Their mere presence in grain renders the grain as low or heavy infested grain

4. • Up to two live insects per kg of grain is low infested one whereas more than two
insects per kg would make it heavily infested grain
• The following well tested method would prevent the infestation of grain by insects
(a) Hygienic methods of insect and pest control.
(b) Hermetic technology of insect and pest control.
(c) Aeration technology.
(d) Heat treatment methods.
(e) Use of Chemicals.

5. • The chemical treatment methods have been accepted as the most popular method of
controlling insects and pests.
• The insecticides commonly used for prophylatic treatment of stored food grain are
Malathion and Dichlorvos.
• Malalthion acts as a contact insecticide. The Dichlorvos (DDVP) has both contact as well
as fumigant action
• Pyretherum is the best known natural insecticide, the most important constituents of
which are known as pyrethrine
• It is non-toxic to human beings and is considered quite safe for use in food grain.
• It can also be used for space treatment or as surface treatment on walls and floors etc.

6. Aeration & Fumigation

7. Aeration
• Aeration is the process of moving air through stored grain at low flow rates to
maintain or improve its quality
• Aeration can provide three major benefits in the storage of grains.
1. It cools the grain and slows down insect activity.
2. By cooling the grain, aeration prolongs the effectiveness of pesticides.
3. It can provide an appreciable drying function

8. Benefits of Aeration
• It prevents storage odours. Grains stored for longer periods often develop
objectionable odours. Aeration provides the grains a new, fresh smell
• It reduces moisture accumulation. Moisture condensation by changes in
temperature and relative humidity can be reduced by aeration
• Application of fumigants through an aeration system is an easy and
practical method for controlling insects in stored grains.

9. • Aeration systems can be installed in both horizontal and vertical storages.
• The following set of basic design parameters are found suitable for cooling of
dry grains by aeration

21. • Before storing grain in bags, disinfecting of empty bags should be done by either dusting or
smoking or fumigation
• During the process of dusting or fumigation, all the openings except one for the operator to
get in and out are closed
• If smoking is to be done, a suitable formulation of Benzene Hexachloride which on ignition
gives out smoke is used. About 10 kg of fumigant is required for 30 cu.m in space
• After filling, the remaining opening should also be closed and locked for about 48 h. After the
expiry of this period, the structure should be opened carefully.
• Nobody should be allowed to come within a distance of 15 m from the storage structure for
some time after opening the doors. After about 4 h, all the doors and openings should be
opened, and should remain open for another 6h
• No one is allowed to enter the structure during this time. It should be remembered that
above process is quite a dangerous one and it should be done under supervision of
experienced and trained operators

22. Hermetic storage
• Hermetic storage (HS) technology has emerged as a significant alternative to other
methods of storage that protect commodities from insects and moulds
• Also known as Sealed storage or airtight storage or assisted hermetic storage
• It is a form of bio-generated modified atmosphere
• It is based on principle of generation of an oxygen-depleted, carbon dioxide enriched
interstitial atmosphere caused by the respiration of the living organisms within the
ecological system of a sealed storage
• Advantage is the generation of a MA in an environmentally safe and sustainable manner,
eliminating the need for chemical treatments, fumigants, and climate control

23. It creates
1. Low oxygen modified atmosphere
• Creation of sufficiently low oxygen and elevated CO2 MA protects from insects, molds and
oxidation effects
• This is done through a natural metabolic process of insect respiration and, in some cases
the respiration of the commodity itself
• When a level of less than 2% oxygen is reached , mortality of all insect stages is achieved
rapidly
2. Preventing entry of moisture from surrounding atmosphere
3. Protection from rodents
• Properly designed hermetic storage is highly rodent resistant
• Rodent resistance is provided in the case of large hermetic enclosurers such as Cocoons
by using trough, slippery materials such as flexible PVC (typically 0.83 mm thick), and
tensioning straps, which prevent rodents from getting a tooth hold

24. Applications of Hermetic Storage
• Long-term storage of cereal grains, primarily rice, corn, barley and wheat
• Long-term storage of a variety of seeds to preserve germination potential and
vigor
• Quality preservation ofb high-value commodities, such as Cocoa and coffee
• Storage of specialized, difficult to store products such as brown rice, rice bran
and basmati rice
• Prevention of growth of toxinogenic aflatoxins in corn and peanuts, or
ochratoxins in coffee
• HS is also used to store oily commodities such as cottonseeds or peanuts to
prevent the growth of free fatty acids (FFAs) and resulting rancidity

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