Articles
ISOLATION OF SAPROPHYTIC YEASTS FROM PISTACHIO FRUITS AND LEAVES
Article number
726_102
Pages
599 – 604
Language
English
Abstract
The Pistachio nut (Pistachia vera L.) is one of the favourite tree nuts of the world.
Aflatoxins are toxic as well as carcinogenic compounds produced by the fungus Aspergillus flavus.
A. flavus is a pathogen infecting pistachios, which have been damaged by insects, animals, early splits and mechanical harvest.
Infection of A. flavus will result in rapid accumulation of aflatoxin in the harvested nuts under conditions of warm temperature and high humidity.
Contamination can occur in the field, at harvest, during post-harvest operations and in storage.
With increasing knowledge and awareness of aflatoxins as a potent source of health hazards, a great deal of effort has been made to completely eliminate the toxin or reduce its content in food to significantly lower levels.
Since removing aflatoxin from pistachios once they are present is impractical and expensive, it is necessary to prevent formation of aflatoxin through biological control of A. flavus. Aflatoxin production can be inhibited by some yeast.
In a research being conducted in Iranian pistachio research institute (IPRI) the potential of yeasts as effective biocontrol agent against A. flavus is being investigated.
To achieve this goal, the first step is; Isolation and Identification of yeasts present on the surface of pistachio leaves and fruits.
For isolation of yeasts, samples from 2 different varieties were collected.
Pistachio fruits and leaves were separately submerged in water containing Tween 80. Suspension was spread on NYDA plates and incubated at 28°C. Selected yeast colonies were streaked on NYDA and Malt Extract plates for single colony isolation.
Microscopic observation, sugar fermentation and gas production was investigated.
Candida, Rhodotorula and Cryptococcus species were identified.
Aflatoxins are toxic as well as carcinogenic compounds produced by the fungus Aspergillus flavus.
A. flavus is a pathogen infecting pistachios, which have been damaged by insects, animals, early splits and mechanical harvest.
Infection of A. flavus will result in rapid accumulation of aflatoxin in the harvested nuts under conditions of warm temperature and high humidity.
Contamination can occur in the field, at harvest, during post-harvest operations and in storage.
With increasing knowledge and awareness of aflatoxins as a potent source of health hazards, a great deal of effort has been made to completely eliminate the toxin or reduce its content in food to significantly lower levels.
Since removing aflatoxin from pistachios once they are present is impractical and expensive, it is necessary to prevent formation of aflatoxin through biological control of A. flavus. Aflatoxin production can be inhibited by some yeast.
In a research being conducted in Iranian pistachio research institute (IPRI) the potential of yeasts as effective biocontrol agent against A. flavus is being investigated.
To achieve this goal, the first step is; Isolation and Identification of yeasts present on the surface of pistachio leaves and fruits.
For isolation of yeasts, samples from 2 different varieties were collected.
Pistachio fruits and leaves were separately submerged in water containing Tween 80. Suspension was spread on NYDA plates and incubated at 28°C. Selected yeast colonies were streaked on NYDA and Malt Extract plates for single colony isolation.
Microscopic observation, sugar fermentation and gas production was investigated.
Candida, Rhodotorula and Cryptococcus species were identified.
Authors
L.A. Hejri, M. Azar, A. Javanshah
Keywords
saprophytic yeast, elimination of aflatoxin
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