Agriculture Reference
In-Depth Information
(a)
Figure 14.24
Primary sorting and grading of
cantaloupe.
(b)
Immature fruits, such as cucumber and summer squash,
have underdeveloped cuticles and consequently readily
lose moisture during handling. In the United States, slicing
cucumbers are typically coated with edible wax, while
European greenhouse types are placed in shrink-wrap
plastic film to control moisture loss. Smaller, Beit Alpha-
type greenhouse cucumbers have less weight loss than the
European types (Lamb
et al
. 2001); Stapleton
et al
. (2002)
reported good quality up to 14 days at 10°C without waxing
or overwrapping, although use of both methods further
reduced moisture loss. Permeability of wax and edible
coatings to water, oxygen and carbon dioxide varies and
must be matched with the respective fruit (Hagenmaier &
Shaw 1992; Baldwin
et al
. 1999).
Figure 14.25
(a) Vertical dividers bear the weight
of stacked cartons, while (b) padding materials from
paper and pulp provide protection against abrasion
during handling.
Packaging
Packages must be selected for strength, cooling method,
end market and cost (Sargent
et al
. 2003). Rigid packages
such as cartons, returnable plastic containers and clamshell
containers provide better protection from mechanical injury
than plastic sleeves and plastic, overwrapped trays. Inserts
and padding materials also provide added protection (Figure
14.25a and 14.25b). Corrugated cartons are often coated
with paraffin wax in North America to protect against
moisture absorption and collapse during hydro-cooling or
shipping, while providing extra stacking strength. Wooden
wire-bound crates have intermediate stacking strength if
cross-stacked, since the end panels provide the stacking
strength. In the case of bulk shipping in field bins or trailers,
care must be taken to avoid crushing fruit at the bottom of
the load from stacking the product too high. The package
footprint (base dimensions) should be designed to
completely cover a standard shipping pallet (40 × 48 inches;
100 cm × 120 cm). This will maximize use of shipping
space while facilitating palletisation (Sargent
et al
. 2003).
Ventilation is important for cooling efficiency. For
example, cantaloupe can be forced-air cooled or hydro-
cooled. Vent openings in side walls of the container must
be of ample size and proper alignment to adequately
remove field heat during forced-air cooling and the heat of
respiration during subsequent handling and storage (Talbot
et al
. 1992). For hydro-cooling or package icing, the
container must be water-resistant and permit drainage.
Openings must be of sufficient size without compromising
the structural integrity of the container. Several of these
design features have been incorporated into returnable
plastic containers (RPCs), contributing to increased
adoption worldwide. RPCs offer convenience in that they
