Detection and analysis of mycoflora associated corn and wheat flours and their toxins

Abstract

Corn and wheat flours are a significant part of the daily diet for millions of people. This work aimed to detect all the fungal flora associations and determine the mycotoxin production in the local corn and wheat flours. All corn and wheat flours were packed in 50kg bags as commercial presentations of each type. Samples were collected from three localities area. These samples were analyzed for mycoflora contaminant using the Potato dextrose agar (PDA) method and tested for mycotoxins production by using HPLC technique for the separation process. The results indicated that, total fungal counts yielded 138 isolates belonging to 40 isolates from corn flour samples, equal to 29%, and 98 isolates from wheat flour samples, equaling 71%. Location (Z) gave a higher total fungal count with corn flour samples which recorded 34 isolates, equal to 85%, followed by location (A), which gave six isolates, equal to 15%. Corn flour samples collected from location (B) were better than others which recorded zero fungal flora percent. On the other hand, location (B) was the most total fungal count isolated from wheat flour samples which record 60 isolates equal 61.2% followed by location (A) which gave 32 isolates equal 32.7% and location (Z) which record 6 isolate equal 6.1%. Five fungal species belonging to three fungal genera were identified from different corn flour samples i. e. Aspergillus niger, A. flavus, A. parasiticus, Fusarium moniliform and Penicillium spp. Aspergillus flavus was the most fungal frequency occurred. Whereas seven fungal species belonging to five fungal genera were identified from different wheat flour samples. These are Alternaria alternate, Aspergillus niger, A. flavus, A. parasiticus, Fusarium moniliform, Penicillium sp., and Rhizopus stolonifer. Detection of mycotoxins presented that, only aflatoxins were produced by some isolates of A. flavus and A. parasiticus. From wheat flour, A. flavus isolate No. A/N/ 5 gave 0.59 ng/g of total aflatoxins, A. flavus isolate No. A/N/ 6 gave 0.71 ng/g of total aflatoxins and A. parasiticus (isolate No. A/N/ 94) gave 0.66 ng/g of total aflatoxins respectively. From corn flour, only Aspergillus flavus No. Z/N/ 22 which isolated gave 0.81 ng/g of total aflatoxins. Fumonisin B 1 was not detected.