Mycoflora associated with 120 walnut samples was examined using agar plate method. Data of isolation frequency were statistically analyzed. Mycotoxin productivity of obtained fungi was assayed using HPLC. Twelve species belonging to six fungal genera were isolated in this work. Aspergillus flavus, Aspergillus niger and Rhizopus stolonifer were the most predominant, with highest distribution over samples. Significant to highly significant positive correlation was found among some isolated fungi. Most of Aspergillus flavus isolates were capable of producing sterigmatocystin, maltoryzine and aflatrem. Meanwhile, all tested isolates of Aspergillus niger were capable of producing oxalic acids ranged from 300-850 mg/ml in the culture media. Both of Fusarium proliferatum and Fusarium subglutinans were toxigenic and varied in their productivities of ipomeanine, neosolaniol, nivalenol and NT-2 toxin. In respect to citrinin and citreovirdin, Penicillium aurantiogriseum was more productive than Penicillium brevicompactum.
Storage fungi, walnut, HPLC, Mycotoxins
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