Title: Occurrence of aflatoxins and aflatoxigenic Aspergillus in peanuts
Abstract: Aflatoxins are carcinogenic mycotoxins mainly produced by Aspergillus flavus and Aspergillus parasiticus. Variety of food and agricultural commodities can be contaminated by Aspergillus spp. High temperature and relative humidity in tropical countries favours growth of Aspergillus and subsequently aflatoxin production in food and feed. In this study, occurrence of aflatoxins and aflatoxin–producing fungi in peanuts was investigated. Sixty raw peanut samples were used for fungal isolation and 83.3% of total samples showed fungal contamination. Morphological studies showed that 46 samples were contaminated with Aspergillus spp. and 23 green aspergilli were isolated from raw peanut samples. The 3 day-old purified Aspergillus isolates grown at 30oC on PDA plates were screened for their aflatoxin-production ability using ammonia vapour and 14 isolates were found to be aflatoxin–producers in the screening test. Pink/red colony reverse represented aflatoxin-producing strains. Aflatoxin production of Aspergillus isolates in culture media was confirmed by HPLC analysis. The isolates found positive by the screening test, showed a sharp AFB 1 peak in their HPLC chromatograms. Aflatoxins were extracted from the culture media as well as peanut samples and were detected using following HPLC conditions: mobile phase (ACN/H2O/MeOH: 8/54/38), temperature 24oC and flow rate 0.4 ml min -1 . Among six raw peanut brands analysed for aflatoxins, five brands showed AFB 1 contamination ranging from 0.62 to 19.27 ng g -1 . One brand which had the highest moisture content (8.08% ± 0.24) was highly contaminated with AFB 1 (977.66 ± 12.19 ng g -1 ). Moisture content of raw peanut samples ranged from 3.98 to 8.08%. Limits of detection (LOD) and recovery of the method for AFB 1 were 0.05 ng g -1 and 93.68-98.94%, respectively.
Publication Year: 2013
Publication Date: 2013-01-01
Language: en
Type: article
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Cited By Count: 16
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