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Information - Cargo Care
Cargo
Care - Infestation & Fumigation
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Causes of Infestation
Cargoes can become infested and damaged by the following common
forms of pest or vermin.
-
Rats consume approximately
their own weight in food per week. The damage that rats can do
to a cargo of foodstuffs
is compounded by
the fact that the presence of rats will almost certainly mean
that the cargo has to be condemned. This is due to the fact that
rats
are carriers of virulent diseases. Control of rats aboard ship
is done by fumigation and a periodic renewal of a "De Rat" Certificate.
In the case of containerised cargo, care should be taken to inspect
the cargo during packing for signs of rats having penetrated
the cargo.
-
Beetles, moths and mites are
known to cause damage to a wide range of commodities. Each insect
grows from an egg produced by an adult
female. The egg of the beetle and moth hatches into a caterpillar
which actively feeds on cargo. This is the greatest cause
of damage from infestation. Caterpillars moult several times during
their life
cycle before entering a pupal stage which releases the moth
to restart the cycle. Mites are hatched from eggs producing an
insect which
goes through a series of development stages before reaching
adulthood.
-
Lice are often found
in bales of rags. A reliable sanitary certificate normally accompanies
the cargo
-
White Ants are found
in certain tropical woods and often in flat dunnage
-
Cockroaches are
found in various cargoes including hollow bamboo and old cord wood
-
Sirex Wood-Wasp is
found in timber dunnage
-
Maggots are found
in animal hoofs, horns, bones and skins.
-
Tropical Warehouse Moth is
found in cocoa beans and coffee
-
Weevils are common
in bran rice
-
Copra Beetle is
found in coconuts and cereals
-
Black Mould Parasite is
found with onions
-
Sitophilus Zeamais is
common in maize
-
Tribolium Castaneum is
found in wheat
flour
Infestation is obvious when insects are visible on bags or bulk,
but it may be that insects are feeding inside the foodstuff itself.
This can happen for example with wheat grains and coffee beans. Tropical
countries are associated with the origins of particular insects,
however cross contamination with other infested cargoes is a common
cause.
There are four types of damage resulting from insect or mite infestation:
-
Boring and nibbling mixed with webbing
and excreta.
-
Loss in weight and heating. It is
important to note that heating can be caused in dry materials solely
by the activity
of insects.
-
Water damage. Essentially a surface
phenomenon confined to the top few inches of the cargo resulting
from "hot
spots" and
insect activity.
-
Depreciation of value. A good
example of this is Tribolium beetles within desiccated
coconuts which
cannot be removed by a commercially
practicable process.
Prevention
Fumigation is the recognised means of combating infestation by the
application of fumes to disinfect or purify. There are several substances
used for this purpose which are listed below. Further sections are
provided on the disciplined procedure necessary for applying fumigants
as well as the relationship to the IMDG code for hazardous cargo.
Types of Fumigants
Methyl Bromide (Bromomethane)
Methyl Bromide, at normal temperature, is a colourless gas 3.27
times heavier than air. The pure gas has a faintly sweet smell but
it normally has a marker added for warning which causes watering
of the eyes.
There is widespread international concern over Methyl Bromide because
of its properties as a category one ozone depletant under the Montreal
Protocol of 1992. Not withstanding its abilities as a fumigant there
is a mounting consensus that a more suitable substance must be found
by the end of the century. Methyl Bromide is highly toxic to mammals
and is the most widely used fumigant for timber, agricultural products,
empty containers, foodstuffs, seeds and plants. In particular Australian
quarantine clearance by AQIS requires this method which includes
fumigation against :
-
Weeds and organisms within soil and
compost,
-
Insects and mites,
-
Infestation in
fresh fruit,
-
Within nursery stocks of plants.
Effect on foodstuffs: After fumigation the bulk of methyl bromide
is removed by aeration although there may be
small residues. There can on occasion be a chemical reaction
with
certain food products
if some absorption takes place.
Methyl Bromide is absorbed by oils, fats and finely ground materials.
It can also react with materials containing sulphur to cause discoloration
or odour. The following materials are among those which should NOT
normally be fumigated by Methyl Bromide:
-
Butter, lard, fats, avocado, soybean
flour, flours and baking powders,
-
Bone meal, charcoal and cinder
blocks,
-
Furs, felts, horsehair, pillows,
rugs and papers,
Iodised salt,
-
Leather goods and photographic chemicals
(excluding film).
-
Photographic prints,
-
Rubber goods,
-
Woollen goods
Health Warning : Exposure to Methyl Bromide has in the past
resulted in a number of deaths. A particular
danger is that signs of poisoning
may be delayed for several hours
following exposure to the gas. There is no significant antidote
and the human
body can absorb it by inhalation
and via the skin. Headache, dizziness,
eye irritation, coughing, nausea, abdominal pains and
numbness of the feet
are early indications
of poisoning. Methyl Bromide
is usually administered
from approved cylinders or cans. It is
important to stress the use of the correct
protective clothing during fumigation.
Guideline quantities : For ANZ destinations - 5.0 lbs per 1000 cft
or 80 gms/cbm For USA destinations - 4.5 lbs per 1000 cft or 72 gms/cbm
For other destinations- 3.0 lbs per 1000 cft or 48 gms/cbm
Phosphine
Phosphine used for fumigation purposes is usually produced by the
reaction of atmospheric moisture with slow release formulations
containing aluminium or magnesium phosphide. Phosphine is highly
toxic although it requires a relatively high temperature and long
exposure period to be effective. Under normal conditions Phosphine
is a gas and is colourless and odourless. A fishy or garlic-like
smell may be evident due to impurities.
A significant fire/explosion risk associated with phosphine is reduced
by using metal phosphides specially prepared for fumigation purposes.
Care must be taken during use to isolate any electrical connection
(switches can be covered in paraffin wax) and any sources of ignition
must be removed.
Phosphine is used for fumigating a wide band of insects and pests.
It has a low degree of absorption by foodstuffs and penetrates well
into the stored product.
Health Warning : Very poisonous and very similar symptoms to those
of Methyl Bromide if exposed to it. A notable effect is chest tightness
and difficulty in breathing.
Phosphine preparations for fumigation are dispensed as :
Sulphuryl Fluoride
Sulphuryl Fluoride (Vikane) is used extensively in the USA
to control insect pests in timber. It should not
be used on living plants and
foodstuffs. It does have an advantage
over Methyl Bromide in that it does not have any harmful effects
on photographic
supplies, metals,
electronic components, paper, leather, rubbers,
plastics and wallpapers.
Ethylene Oxide
Approval for use in foodstuffs was withdrawn by Australian authorities
(AQIS) in 1988 due to concern over toxicity of residues formed
in some foods. The properties of Ethylene Oxide as an insecticide
and effectiveness in devitalising seeds make it specific to special
needs such as fumigating rice straw matting.
A major drawback is the explosive qualities of Ethylene Oxide requiring
it to be normally applied under vacuum.
Ethylene Dibromide (EDB)
Used for years as a treatment for fruit fly in fresh fruit and vegetables
and agricultural needs this form of fumigation has gradually been
replaced.
Reference to the IMDG Code
Reference is made to the IMO/ILO guidelines for packing cargo in
freight containers or vehicles and recommendations on the safe use
of pesticides in ships.
Only a cargo transport unit that can be closed in such a way that
the escape of gas is reduced to a minimum, should be used for the
carriage of fumigated cargo.
A closed cargo transport unit under fumigation should not be allowed
on board until sufficient time has elapsed to allow the attainment
of a reasonably uniform gas concentration throughout the cargo. Because
of variations due to types and amounts of fumigants and commodities
and temperature levels, the period which should elapse between fumigant
application and loading should be determined by the competent authority.
Twenty four hours is normally adequate for this purpose.
The master should be informed prior to loading of a cargo transport
unit under fumigation. These should be identified with a warning
sign affixed to the access doors incorporating the identity of the
fumigant and the date and time of fumigation. The transport documents
for a closed cargo transport unit should show the date of fumigation
and the type and amount of fumigant used.
Equipment for detecting the fumigant gas or gases should be carried
on the ship, with the instructions for its use. Fumigants should
not be applied to the contents of a cargo transport unit once it
has been loaded aboard a ship.
The provisions of this code should NOT apply to a closed cargo transport
unit which has been ventilated after fumigation to ensure that no
harmful concentrations of gas remain. Such a unit should also have
the warning signs removed.
Health & Safety
Due to the very serious hazards, both health and fire, associated
with fumigation, only competent specialist people should be employed
to undertake this operation. When opening a container which has
undergone fumigation, care must be taken to guard against residual
levels of the fumigant. This will depend on the time since fumigation
and the amounts applied. The container must be properly ventilated
and suitable equipment used (Draeger Sets) to measure for residual
gas prior to unstuffing.
How to Apply Fumigants
As a general rule there must be a minimum of two person conducting
any fumigation.
- Secure fumigation sit: Fumigation
should be conducted at an approved and isolated area specially
designated for this purpose. Notification
of planned fumigation should always be provided
to relevant parties so that the danger to staff is flagged in
advance.
- Protective Equipment: Special protective suits
are required which have respiratory protective equipment (RPE).
This equipment
must
be maintained properly and tested at regular intervals.
Inspect container prior to stuffing to ensure that
there are no holes in the container's side panels,
roof, floor or doors.
- Seal any ventilation ducts
on the OUTSIDE of the container using grip tape or suitable equivalent.
- Ventilated containers must be sealed along their
top and lower side vents on the outside.
- On completion of stuffing
and observing the relevant safety procedures referred to previously,
the
fumigant is applied inside the container,
with a door cracked open, and doors then quickly
closed.
- The amount and type of fumigant will
be determined by the temperature, commodity, cargo cubic
and country of destination. (See guidelines
under Methyl Bromide and Phosphine).
- A competent
contractor will have a chart to readily determine the amount
required. If it
is the intention
to ship the cargo under fumigation
then the cargo must be treated as IMO Haz
Class 9 and booked through the existing
company procedures
for hazardous cargo. The relevant
packing declaration must accompany the
cargo and the container appropriately labeled.
- At least 24 hours
must elapse after fumigation prior to the container being shipped.
The
reason for this is to allow the fumigant
to properly
permeate the cargo. In cases where the
cargo requires ventilation during the
voyage e.g.
Coffee, the
vents must be unsealed prior to
shipment. In this case the container
should be rendered non hazardous by opening the
doors to
fully vent the container prior to shipment.
- A gas free certificate should be issued by the
company conducting fumigation
operations which
then exempts the cargo from hazardous
regulations. If shipping gas free then
time
scales must be carefully considered
up to the arrival
of the ship designated to lift the
cargo. Sufficient time must be given to allowing
the fumigant to act as well as making
the container
gas free
afterwards. Fumigation can
also be carried out on arrival at the
destination port and will be subject
to the port health
requirements of that country.
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