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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Chemical Control 111
Sanosil-25, a disinfectant containing 48% hydrogen peroxide, and
silver salts as stabilizing agents, inhibits spore germination and mycelial
growth of Alternaria alternata, Fusarium solani and B, cinerea, and
markedly decreases decay in melons at 5000 ^11^ when incorporated into
a wax treatment, without causing any phytotoxic effects (Aharoni et al.,
1994). Dipping commercially harvested eggplants and red peppers in
0.5% Sanosil-25 reduced decay development by A alternata and
B. cinerea after storage and shelf life, to a commercially accepted level
(Fallik et al., 1994a). On the other hand, immersion of Penicillium
digitatum-m.OQX)ldiiedi lemons in hydrogen peroxide at 5-15% did not
effectively control the green mold and caused unacceptable injury to the
fruit when the immersion period was increased to 90 s (Smilanick et al.,
1995).
Acetic acid and other short-chain organic acids, such as propionic
acid, are commonly used by food manufacturers as antimicrobial
preservatives or acidulants in a variety of food products (Davidson and
Juneja, 1990). The possibility of using vaporized acetic acid against
postharvest decay has been studied in various fruits (Sholberg, 1998;
Sholberg and Gaunce 1995, 1996; Sholberg et al., 1996). Sholberg and
Gaunce (1995) found acetic acid, applied as a vapor at low concentrations
in air (2-4 mg l-i), to be extremely effective in reducing or preventing
decay in: various cultivars of apples and Anjou pears inoculated with
B. cinerea and Penicillium expansum conidia; tomatoes, grapes and
kiwifruit inoculated with B, cinerea; and Navel oranges inoculated with
Penicillium italicum. The same authors (Sholberg and Gaunce, 1996)
found acetic acid to be similarly effective as a postharvest fumigant on
stone fruits, controlling decay by Monilinia fructicola and Rhizopus
stolonifer at concentrations in air as low as 1.4 mgl-^. On table grapes,
fumigation with 0.27% (vol/vol) acetic acid controlled Botrytis and
Penicillium decay as effectively as sulfur dioxide applied at commercial
rates (Sholberg et al., 1996). This treatment has been suggested as an
alternative to SO2 fumigation, that could provide the table grape
industry with many benefits. While SO2 treatment leaves sulfite residues
on the surface of the berries, acetic acid does not leave any toxic residues
on grapes, and no differences from SO2 in terms of external fruit quality
and fruit composition have been recorded. Furthermore, wine grapes
could also benefit from fumigation with acetic acid (Sholberg et al., 1996).
Sholberg (1998) found that fumigation with acetic acid (1.9 nl l-i), and
other closely related short-chain organic acids, formic (1.2 |LI1 l-i) and
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