title: Monitoring of aflatoxin G1, B1, G2, and B2 occurrence in some samples of walnut.
abstract: This research was conducted to monitor the aflatoxigenic fungi and aflatoxin contamination of walnut in the Hamedan province. For this purpose, 40 samples were analyzed. Aspergillus, Alternaria, Rhizopus, Cladosporium, Fusarium, yeast, and some different bacteria were isolated from walnuts. Aspergillus is the most frequent genus. Aspergillus flavus was predominantly isolated. HPLC was used for evaluation of aflatoxin contamination of walnut samples. Aflatoxins G1 (AFG1), B1 (AFB1), G2 (AFG2), and B2 (AFB2) were produced by 20 isolates. AFG1 and AFB1 were being predominant at concentration ranges of 1.7-18.2 and 0-8.2 ngg-1, respectively. Highest levels were found in one sample that was highly contaminated with Aspergillus flavus/Aspergillus parasiticus. Methyl beta cyclodextrin also was performed for detection of aflatoxigenic Aspergillus isolates. The results showed that only 31.6% (p < 0.05) of A. flavus and A. parasiticus isolates were able to produce aflatoxin. A significant difference was shown between shielded and unshielded walnut in aflatoxin contamination. The content of aflatoxin in most of the walnut samples did not reach to maximum tolerable limit for aflatoxin B1 in EU standard (p > 0.05). Thus, systematic and continues monitoring of walnuts is recommended.
authors.affiliation: Department of Microbiology, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran. habiby.reza@gmail.com.
authors.forename: Reza
authors.initials: R
authors.lastname: Habibipour
authors.affiliation: Department of Microbiology, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
authors.forename: Parisa Rahimi
authors.initials: PR
authors.lastname: Tamandegani
authors.affiliation: Department of Chemistry, Young Researchers and Elite Club, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
authors.forename: Abbas
authors.initials: A
authors.lastname: Farmany
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis*; D000348:Aflatoxins / Q000032:analysis*; D001231:Aspergillus flavus / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid; D004784:Environmental Monitoring / Q000379:methods*; D031324:Juglans / Q000737:chemistry* / Q000382:microbiology; D009754:Nuts / Q000737:chemistry / Q000382:microbiology
chemical_list: D000348:Aflatoxins; C027955:aflatoxin G1; C029754:aflatoxin G2; C029753:aflatoxin B2; D016604:Aflatoxin B1
keywords: Aflatoxin; HPLC; Walnut