Post harvest diseases fruits and vegetables - Xavier University ...

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Physical Means 213
In Penicillium digitatum-mocnlsited citrus fruit, a combined treatment
of hot water (52°C, 5 min) and gamma irradiation (0.5 kGy) delayed the
appearance of green rot by 33-40 days (Fig. 36) (Barkai-Golan et al.,
1969). Combining irradiation (0.75 kGy) with the conventional hot water
treatment (50°C, 10 min) prolonged the shelf life of papayas by 9 days
beyond the prolongation achieved by heating alone, facilitating the
distribution of South African fruits within that country and making
large-scale export by sea possible (Brodrick and Thomas, 1978). Hot
water (55°C, 5 min) plus irradiation (0.75 kGy) also act synergistically in
controlling anthracnose (Colletotrichum gloeosporioides) in mangoes.
This treatment is commercially used for treating mangoes in South
Africa, both for decay control and for quarantine control of the mango
seed weevil (Sternochetus mangiferae) (Brodrick and Thomas, 1978).
A study on South African cultivars of plums and nectarines has shown
that a hot water dip (46°C, 10 min) enabled the suppression of postharvest
100
•5 60 +
c
o
a:
30 40 50 0 20
Days after inoculation
Control #-
Irradiation only A k
Heat only (3 min) Irradiation + 3 min. Heat A A
Heatonly (5min)o----0 Irradiation + 5 min. Heat A A
40 50
Fig. 36. Effects of combined treatments of heat and gamma radiation upon
inactivation of Penicillium digitatum in inoculated Shamouti oranges.
(Reproduced from Barkai-Golan et al., 1969 with permission of the American
Phytopathological Society).
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