Journal of Pure and Applied MicrobiologyVol. 6 No. 4

Study on the Amount and Type of Aflatoxin Produced by Aspergillus flavus in Some Pistachio Cultivars of Khorasan-e-Razavi Province

Leila Jalali1*, Hossein Afshari2, Shahram Ashraf3 and Abdol Ghaffar Ebadi4

1Department of Plant Protection, 2Department of Horticulture, 3Department of Soil Science, Damghan Branch, Islamic Azad University, Damghan, Iran. 4Department of Agriculture, Jouybar Branch, Islamic Azad University, Damghan, Iran.

Received on 25 September 2012 and accepted on 12 November 2012

 

ABSTRACT

In order to measure the amount and type of aflatoxin produced in various cultivars of pistachio from Khorasan e Razavi Province, 4 cultivars of popular pistachio of Khorasan-e-Razavi were selected and collected. For this research, an isolate of aflatoxigenic Aspergillus flavus separated from the pistachio was used. Initially, 60 grams of pistachio kernels in 3 consecutive 20-gram sampling were selected and placed on Petri-dishes separately. 1 ml of the spore suspension of aflatoxigenic Aspergillus flavus added to each Petri-dish (spore suspension adjusted to contain of 2 ? 106 spore/ml). The plates placed over water in plastic boxes and then placed inside an incubator at 26C. After 5 and 8 days of inoculation, growth rate and colonization of A. flavus on pistachio kernels measured in different cultivars. For the purpose of extraction of aflatoxin from pistachios; initially, contaminated pistachio nuts are dried inside the oven with a temperature of 60 C for 48 hours to prevent the fungi from growing and further production of aflatoxin. Then, the amount and type of aflatoxin in pistachios were analyzed with HPLC method. The results of the study demonstrated that among the examined cultivars, this isolate is able to produce both aflatoxin B1and B2. It is noteworthy that the isolate is not able to produce aflatoxins G1 and G2.The highest amount of aflatoxins B1 and B2 produced was for Daneshmandi cultivar and the lowest figure was for Garmeh.

Keywords : Khorasan-e-Razavi Province, Aspergillus flavus, Pistachio, Aflatoxin, HPLC.