Agriculture Reference
In-Depth Information
quality and vase life has meant that shipping over longer
distances has not been practised widely.
Flowers can benefit from controlled atmosphere (CA)
cold storage (e.g. daffodil/narcissus and carnations; Nowak
& Rudnicki 1990; Macnish
et al
. 2009). However, normal
low-temperature cool storage rooms are typically used.
Similarly, hypobaric (reduced pressure) cold storage has
been shown beneficial, but is not currently economically
feasible (Halevy & Mayak 1981; Nowak & Rudnicki 1990;
Macnish
et al
. 2009). Modified atmosphere packaging
(MAP), which encloses flowers in a semi-permeable
plastic film, has received limited use on flowers. MAP
extends the life of some flowers (e.g. carnations) as long as
temperatures are maintained at low and constant levels.
However, this condition is often not possible in commercial
practice, particularly in air transport.
Ethylene removal from cold rooms by ventilation at
about one air change per hour and, less successfully, by
scrubbing with activated charcoal or permanganate is
perhaps warranted for cut flowers (Halevy & Mayak 1981;
Nowak & Rudnicki 1990; Reid 2002). However, effective
protection of ethylene sensitive flowers is best achieved
by STS or 1-MCP.
shipping. Where rail transport of cut flowers is a viable
option, refrigerated boxcars should be used. Refrigerated
sea containers are similarly useful. These can be fitted with
equipment to generate and/or maintain CA conditions. CA
shipping by sea might be appropriate for comparatively
durable cut flowers, which respond positively to CA, like
bud stage carnations (Macnish
et al
. 2009).
Re-cooling of cut flowers at various steps in the handling
process can be helpful in maintaining the post-harvest cold
chain. For example, cut flowers may need pressure cooling
upon arrival at an importer's premises following non-
refrigerated air transport. Similarly re-hydration of cut
flowers may be useful after shipping or storage. This
process involves re-cutting the stems and standing the cut
flowers in clean water containing germicide, acidifier
and/or surfactant, or a commercial post-harvest solution.
Re-hydration can be facilitated by high RH and low air
velocity, and is ideally done at low temperature. For
instance, with the cut flowers standing under loose plastic
shrouds in buckets of re-hydration solution arranged in a
cold room.
Flowers need to be handled gently during transport to
avoid physical damage. Above all, transport needs to done
as quickly as possible to ensure maximum flower life and
quality in the hands of the consumer.
Transport
Road and air are the main modes of transport for cut
flowers (McGregor 1987; Nowak & Rudnicki 1990). Sea
and rail transport are comparatively rare. Nonetheless, sea
shipment of cut flowers and foliage is routine on the major
trade route from South to North America. Trucks fitted
with mechanical refrigeration units are used to move cut
flowers within regions and between regions and countries,
such as throughout Europe and North America. In contrast,
air transport is more typically used for intercontinental
shipping, such as from Australia to Japan. Refrigeration is
usually not possible during the air transport, though it is
now being introduced by at least one airline. However, ice
or other cryogenic compounds such as dry ice can be
included in packages and/or in the air container to remove
incoming radiation heat and vital heat of respiration,
particularly if the flowers and ice are insulated to minimise
incoming heat (Wills
et al
. 1998). For this approach to be
effective, the latent field heat must have been removed
prior to shipment. In the absence of provisions for in-transit
cooling, ventilation of cut flower cartons may help to limit
both the heat load from respiration and ethylene
accumulation. Some ventilation can be achieved by leaving
the pressure cooling holes open. Thermal blankets and
reflective foils may also be of use in restricting incoming
heat and hence flower warming during nonrefrigerated
Costs and benefits of post-harvest practices
The benefits that are likely to result from post-harvest
treatments include reduced losses due to wilting, flower
drop and poor flower opening; increased sales as a result of
customer satisfaction; and savings in labour and time
because there are fewer problems to deal with.
The greatest costs of post-harvest handling are labour
for picking; labour for grading, treating and packing; trans-
port to market; and cartons. In relative terms, the cost of
post-harvest chemicals and pesticides is very small
(Faragher
et al
. 2002).
MARKETING AND CONSUMPTION
Marketing
Cut flower trading occurs at local (farm gate), regional
(farmers' market), national (central market) and interna-
tional (export-import) levels. The sales and distribution
process can be complex. For example, flowers grown in
Kenya may be sold at auction in Holland and used in
bouquets for sale at a supermarket in the United Kingdom.
Some markets have adopted the Dutch auction clock
system, where as the initially high price falls the buyers bid
to stop the clock at the price they are willing to pay (Plate
