Introduction and Overview - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 10

surveys indicate the need for continued improvements in
temperature maintenance throughout the produce handling
systems.

to exporting countries and for markets that prefer organic
produce.
At the commercial level, CA is most widely applied
during the storage and/or transport of avocados, bananas,
kiwifruits, mangos, persimmons, pomegranates, and nuts
and dried fruits. Continued technological developments in
the future to provide CA during transport and storage at
reasonable cost (positive benefit/cost ratio) are essential to
expanding its application on fresh tropical and subtropical
fruits.

Modified and controlled atmospheres
Continued research on technologies to reduce water loss
included the use of polymeric films (Ben-Yehoshua, 2005)
and surface coatings (Baldwin, 1994; Amarante and Banks,
2001). The use of polymeric films for packaging produce
and their application in modified atmosphere packaging
(MAP) systems at the pallet, shipping containers (plastic
liners), and consumer package levels continues to increase
(Kader et al., 1989; Beaudry, 2000; Watkins, 2000). MAP
(usually to maintain 2-4% O 2 and 8-12% CO 2 ) is widely
used in extending the shelf life of fresh-cut fruit products.
The use of absorbers of ethylene, carbon dioxide, oxygen,
and/or water vapor as part of MAP is increasing. Although
much research has been done on the use of surface coatings
to modify the internal atmosphere within the commodity,
commercial applications are still very limited due to the
variability of the fruit's gas diffusion characteristics and
the stability and thickness of the coating.
Several refinements in controlled atmosphere (CA) stor-
age technology have been made in recent years (Yahia,
2009). These include the creation of nitrogen on demand
by separation from compressed air using molecular sieve
beds or membrane systems, use of low (0.7-1.5%) O 2 con-
centrations that can be accurately monitored and controlled,
rapid establishment of CA, ethylene-free CA, programmed
(or sequential) CA (such as storage in 1% O 2 for 2-6 weeks,
followed by storage in 2-3% O 2 for the remainder of the
storage period), and dynamic CA, where levels of O 2 and
CO 2 are modified as needed based on monitoring some
attributes or produce quality such as ethanol concentra-
tion and chlorophyll fluorescence. Despite the extensive re-
search and development efforts of hypobaric storage (Burg,
2004), its commercial use is very limited.
The use of CA in refrigerated marine containers con-
tinues to benefit from technological and scientific devel-
opments. CA transport is used to continue the CA chain
for some fruits (such as kiwifruits) that had been stored in
CA since harvest. CA transport of bananas permits their
harvest at a more fully mature stage, resulting in higher
yield. CA transport of avocados facilitates the use of a
lower temperature (5 ◦ C) than if shipped in air because CA
ameliorates chilling injury symptoms. CA combined with
precision temperature management may allow nonchemi-
cal insect control in some commodities (Mitcham, 2003)
for markets that have restrictions against pests endemic

Reducing undesirable effects of ethylene
The promotion of ripening and senescence in harvested
fruits by ethylene ( 0.1 ppm) results in acceleration of de-

terioration and reduced postharvest life. Ethylene induces
abscission of fruits, softening of fruits, and several physio-
logical disorders (Abeles et al., 1992; Reid, 1995). Ethylene
may increase decay development of some fruits by acceler-
ating their senescence and softening, and by inhibiting the
formation of antifungal compounds in the host tissue. In
some cases, ethylene may stimulate growth of fungi such
as Penicillium italicum on oranges (Sommer, 1989).
Low temperatures, controlled or modified atmospheres
(Kader, 1986a), and ethylene avoidance and/or scrubbing
techniques are used to reduce ethylene damage. The discov-
ery of the ethylene action inhibitor 1-methylcyclopropene
(1-MCP) in the early 1990s (Sisler and Blankenship, 1996)
was a major breakthrough. In July 2002, 1-MCP (under the
trade name “SmartFresh”) at concentrations up to 1 ppm
was approved by the US Environmental Protection Agency
for use on apples, apricots, avocados, kiwifruit, mangoes,
nectarines, papayas, peaches, pears, persimmons, plums,
and tomatoes. The first commercial application has been
on apples to retard their softening and scald development
and extend their postharvest life during air and CA storage.
As more research is completed, the use of 1-MCP is being
extended to several other commodities (Blankenship and
Dole, 2003; Sozzi and Beaudry, 2007; Watkins, 2008).

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Postharvest pathology
Currently used treatments for decay control include (1)
heat treatments (Lurie, 1998; Paull and Chen, 2000), such
as dipping mangoes for 5 min in 50 ◦ C water to reduce
subsequent development of anthracnose; (2) use of safer
postharvest fungicides, such as Fenhexamid and Fludiox-
onil; (3) use of biological control agents (Wilson and
Wisniewski, 1989; Droby et al., 2009), such as “bio-
Save” ( Pseudomonas syringae )and“Aspire”( Candida ole-
phila ) alone or in combination with fungicides at lower