Agriculture Reference
In-Depth Information
(a)
Figure 9.3
Loaded pallets coming from the field
often pass through a “pallet squeeze,” a device that
straightens and tightens the stacks of containers.
These pallet loads are unitized, usually by strapping
or netting.
(b)
clam shells are perforated to maintain ventilation and thus
reduce microbial decay. A restricted cluster bag with 1.4%
perforation (compared to about 60% perforation for stand-
ard bags) was patented in 2000. Research has shown that
these bags can restrict water loss and slow shrivelling of
the fruit and stem browning without affecting decay and
phytotoxicity levels (Davis
et al
. 2000).
Individual bunch packs are then placed into cartons
which come in a variety of forms including wooden ended
technical kraft veneer (TKV) crates, returnable plastic
crates ('RPCs'), corrugated cardboard 'shoe' boxes and
polystyrene (Styrofoam) boxes. TKV and Styrofoam boxes
are mainly used for grapes destined for longer storage
periods because they maintain their structural integrity in
high-humidity conditions better than corrugated boxes.
Carton dimensions will depend on the pallet size in use in
particular markets (Vidaud
et al
. 1993). Detailed studies of
the relationship between pack volume and packing height in
the box versus grape quality have been carried out for the dif-
ferent box materials and sizes (Luvisi
et al
. 1995). Additional
cushioning separators in cartons have been found to reduce
physical damage to the grapes but the use of absorbent materi-
als can accelerate weight loss (Mencarelli
et al
. 1994).
(c)
Figure 9.2
(a)The most common field-packing system
in California is the 'avenue pack'. (b)The grapes are
picked and placed into shallow plastic picking lugs.
The picking lug is then transferred a short distance to
the packer, who works at a small, shaded portable
stand in the avenue between vineyard blocks. (c) It is
common for the packer and several pickers to work
as a crew. Packing materials are located at the
packing stand, which also shades the packer.
Palletisation
After packing with grapes, cartons are palletised on
disposable or re-cycled pallets. Often loaded pallets
coming from the field pass through a 'pallet squeeze', a
device that straightens and tightens the stacks of containers
(Figure 9.3). These pallet loads are unitised, usually by
strapping or netting. In shed-packing operations, some
