Isolation and Identification of Toxin-Producing Fungi Contaminating Nuts and Their Potential Protection Using Mustard Oil

Abstract

The current study aimed to isolate and diagnose mycotoxin-producing fungi from nuts (pistachios, hazelnuts, popcorn and cashews) and the possibility of reducing their presence using mustard oil. The results obtained confirmed the presence of seven fungi, with the dominance of A. niger, followed by Penicillium sp., Fusarium sp., Alternaria sp., Cladosporium sp., Mucor sp. and Rhizoctonia solani. The results of separation by thin layer chromatography (TLC) showed that 19 out of 30 A. niger isolates were ochratoxin A producers. The results showed that mustard oil inhibited the growth of A. niger tested on PDA culture medium. The inhibition rate increased with increasing the concentration of mustard oil, with highest inhibition rate (59.25%) at the 15% oil concentration, followed by 53.08% inhibition for the 10% oil concentration and 48.14% inhibition for the 5% oil concentration, with significant differences at P=0.05.

Keywords:

Mycotoxins, ochratoxin A, mustard oil, A. niger.