Kiwifruit, Guava, Passion Fruit and Lychee - Crop Post-Harvest: Science and Technology - page 290

four to six weeks (Snowdon 1990). Storage at 20°C and
60% relative humidity reduces shelf life to 3-5 days.
Work in Australia by Olesen et al . (2003) showed that
cvs. Kwai May Pink and Wai Chee were affected by the
storage temperature and the method of cooling (air- or
water-cooling). Chilling injury was apparent at 2°C and the
fruit had poorer colour characteristics with lower L and
chroma, and higher hue angle. Water loss was also greater
than in fruit kept at 5°C. Although lychee at 5°C retained
colour, had lower water loss and less rot development
than fruit held at 10°C or 15°C, these temperatures were
adequate for about two weeks of storage. Water-cooled
fruit had more rot and worse colour retention than
air-cooled but water loss was less.
Olesen et al . (2003) also investigated the effects of
storing fruit at combinations 5°C, 10°C and 15°C during
three consecutive 80 h periods. They found that lychee
at 5°C during the third 80 h period had the least rot,
irrespective of whether the fruit had been held at 5°C, 10°C
or 15°C during the first period. The authors described cool
chain handling of lychee in Australia as 'perverse', since
most effort went into cooling the fruit immediately
after harvest when it was most resistant to variations in
temperature, but its retailing at room temperature just when
refrigeration was most needed. Lychee should be displayed
and retailed from refrigerated cabinets, preferably in
polystyrene containers or plastic bags. It is important that
the fruits are not exposed to ambient air since this causes
rapid skin browning (Paull et al . 2002).
The temperature of lychee on arrival in Sydney ranged
from 0°C to 20°C, often in mixed loads with no option to
impose refrigeration temperatures. Although the tempera-
ture during the early post-harvest period was less critical
than later on, condensation during temperature changes
may enhance the development of moulds. Therefore the use
of packaging that maintains high humidities while mini-
mising the occurrence of free water should be considered.
Minimising temperature fluctuations by ensuring fruit are
pre-cooled to 5°C prior to packing, followed by wrapping
pallets with temperature regulating blankets during trans-
port has been suggested by Olesen et al . (2003).

dips, and cool storage are used to reduce disease losses
(Johnson et al . 2002). Sulphur dioxide fumigation has been
the main post-harvest handling technology to prevent
browning and maintain fruit quality. Fruit exposed to
sulphur may appear slightly bleached (Menzel 2002).
Fumigation with SO 2 has been widely used in South Africa
and Israel, and experimentally in China and Thailand.
However, its continued use may be limited because of
concerns about residues, taint and bleaching of the pericarp,
though the colour gradually returned after removal of the
pads (Mitra 2002).
Hot thiabendazole at 50-52°C was found to be an
effective replacement of hot benomyl, at the same tempera-
ture, as a dip in controlling Alternaria alternata , Phomopsis
sp and other fungi on cv Bengal during storage at 5°C for
up to 30 days. However, dipping cv. Kwai Mai Pink was
less effective because pericarp heat damage interacted
with disease expression. Tainting was a drawback in the
use of prochloraz (Johnson et al . 2002).
In Australia, under-mature lychee developed fewer rots
than mature or over mature fruits with no significant
differences in the deterioration of mature and over mature
types. There was a 20% increase in harvested weight
between each of the maturity stages and so there was a
risk of a possibly large yield loss due to harvesting under-
mature fruit (Olesen et al . 2003).
Fruits inadequately fumigated were prone to infection
by Penicillium spp. On cv. Bengal, storage at 5°C delayed
disease expression for up to 16 days. The main post-harvest
pathogens were A. alternata, Colletotrichum gloeospori-
oides (Penz.) Sacc., C. acutatum Simmonds ex Simmonds
and Pestalotiopsis sp. (Johnson et al . 2002) with
Cladosporium and Penicillium also contributing to post-
harvest decay; these fungi mainly infect the fruit in the
field and then remain dormant until after harvest (Menzel
2002). A review of Australian post-harvest diseases of
lychee is given by Coates et al . (1994).
Olesen et al . (2004) showed that several products and
biological agents already registered for use on other crops
or products in Australia reduced levels of rot when applied
post-harvest; these included acetic and lactic acid,
potassium silicate, and biocontrol with Trichoderma sp.
Although field application of these agents modified the
microflora on the surface of the fruit, no post-harvest
benefit was observed, probably because spraying stopped
two weeks before harvest. This may be unnecessary since
these products are registered in other crops as post-harvest
dips and food additives.
Olesen et al . (2003) also assessed post-harvest rot
development on a commercial packing line, collecting

Ethylene
Lychee is nonclimacteric, and produces less than 0.5 l kg −1 h −1
ethylene at 20°C. Excess ethylene may accelerate aril
breakdown and decay (Kader 2000b).

Pests and diseases
Given its high perishability, sulphur dioxide fumigation,
modified atmosphere packaging, fungicide and hot-water