Agriculture Reference
In-Depth Information
maintenance. Shipping containers with atmosphere-monitoring capabilities
are in service, providing greater opportunities for CA storage of tropical
commodities when the cost can be justifi ed.
POSTHARVEST HANDLING
Most fresh fruits and vegetables are harvested by hand, sometimes with
mechanical aids. Hand-harvesting is accurate, causes minimum damage,
allows fl exible use of labour and requires minimal capital investment in
equipment. When fruit is hand-harvested, the supervision of fi eld labour is
greater, to ensure that the correct fruit maturity is harvested and diseased
and contaminated fruits are not collected (Thompson, 1996). The trend in
tropical fruit production is to maintain tree height to less than 3 m so that all
fi eld operation, including harvesting, can be done from the ground. When
mechanical harvesting aids are used in the fi eld, such as ladders and moving
harvest platforms, harvest rate is slower and has a higher potential for worker
injury and hence liability. Mechanical harvesting is used for fruit that is
destined for processing as it is more rapid and requires less management,
though it causes more mechanical injury.
During collection in the fi eld and transport to the packing area, fruit
should be protected from mechanical injury and high temperatures due to
direct exposure to the sun. Upon arrival at the packing area, the fruits are
normally washed, cleaned and graded, and unsuitable fruit culled; sometimes
fruits are coated with waxes or other barrier compounds to reduce water loss
and improve appearance, and the fruit is treated for disease control, often in
the coating materials, before being packed into shipping cartons. The washing
is done to remove dust and other contaminants. Potable water should be
used, with chlorine or another sanitizer added to reduce cross-contamination
of fruit. Chlorine is the most common sanitizer, available in a number of
formulations, and requires 100-150 ppm of chlorine ion at pH 6-7.5 and
a contact time of 1-2 min. Fruit should be rinsed with potable water upon
removal from the chlorine solution.
National, international and commercial grade standards are used to cull
fruit that does not meet the standards. The standard used will depend upon the
market requirement. The grade standards include a description of maturity,
skin colour, fi rmness, shape and size, and freedom from decay, defects,
mechanical injury and physiological disorders. The standards also include
percentage of of -grade fruit allowed in a batch of fruit. Skin colour charts are
published for many fruits, such as banana, pineapple and papaya.
Packing into cartons or other containers (clamshell) is done to aid in
marketing. The package needs to meet the following requirements: protect the
fruit from injury, allow temperature management, protect the fruit from water
