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

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Postharvest Disease Summary 315
Elevating the CO2 content of the atmosphere to 20-30% is a known
procedure for suppressing decay in strawberries during transit. A level
of 20% CO2 both reduces decay in strawberries and retards their
softening, without injuring the berries or impairing their flavor (Harris
and Harvey, 1973). Reduced decay can also be achieved by wrapping
strawberries in polyvinyl chloride (PVC) film which leads to the
accumulation of a high level of CO2 within the package (Aharoni and
Barkai-Golan, 1987). Low O2 concentrations can reduce both B, cinerea
and R. stolonifer decay in stored strawberries, but excessively low O2
results in the development of persistent off flavors in the fruit as a
result of the accumulation of alcohols and aldehydes in the tissue
(Sommer, 1982). Storing blueberries in 15-20% CO2 at 2°C for 7-14 days
reduced the decay caused mainly by B. cinerea, Alternaria spp. and
Colletotrichum spp. and prolonged the shelf life of the fruit (Ceponis
and Cappellini, 1985).
Several investigators have studied the reduction of postharvest
diseases of strawberries by antagonistic organisms. Preharvest spraying
of strawberry flowers with antagonistic non-pathogenic isolates of
Trichoderma species reduced the incidence of gray mold in storage
(Tronsmo and Dennis, 1977). Storage diseases of both B. cinerea and
R, stolonifer were reduced after application of the yeast-like fungus,
Aureobasidium pullulans to strawberries grown under plastic tunnels
(Lima et al., 1997). The antagonistic effect was more pronounced when
the fungus was applied at the flowering stage, and under these
conditions the antagonistic fungus was more effective than the fungicidal
treatment (vinclozolin). Moline et al. (1999) found that of the many
bacteria isolated from the surface of non-treated strawberries, the most
effective ones were species of Pseudomonas and Chryseobacterium, which
were capable of reducing the incidence of gray mold under field
conditions.
GRAPES
The major postharvest problems of grapes are desiccation, bruising
and decay (Capellini et al., 1986), decay being directly related to
bruising. The main decay pathogens of cold-stored grapes at -1°C are
Botrytis cinerea, Cladosporium herbarum, Alternaria spp., Rhizopus
stolonifer, Aspergillus niger and Penicillium spp. (Hewitt, 1974; Nelson,
1985).
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