Identification of Aflatoxigenic Fungi and Detection of Their Aflatoxin in Red Chilli (<i>Capsicum annuum</i>) Samples Using Direct Cultural Method and HPLC

Abstract

Aflatoxins are the potential lethal toxin produced by Aspergillus sp. important health hazard throughout the world. In this study, 26 Aspergillus sp. have been isolated from 50 samples of red chilli collected throughout the country. These 26 isolates were grown primarily on agar media to identify the aflatoxin producing species. It is possible to distinguish A. flavus strains from other Aspergillus sp. developing orange colour on the reverse of the plates. The Coconut Cream Agar (CCA) is used to detect aflatoxin producer strains having blue fluorescence when exposed to a UV-light. Several other media were used for morphological characteristics of Aspergillus sp. Out of 26 isolates, four isolates were confirmed as Aspergillus sp. These isolates were subjected to cross contamination with freshly ground, sterile maize and after 15 days of incubation the contaminated maize were analyzed by HPLC and found aflatoxin in each of the sample containing 186 ppb (max.). This study was conducted to assay the ability to produce aflatoxins by the Aspergillus spp. isolated from red chilli (Capsicum annuum L. Solanaceae) available throughout the country. The results found in the experiment are much more behind the acceptable limit according to some international standard. As red chilli is a widely used spice in Bangladesh, the proper controlling measures may be taken for controlling the surveillance of aflatoxinic fungi like as use of bio-pesticides, proper drying method and storage conditions.

Isolation of Aflatoxigenic Aspergillus flavus from Animal-Feed and Exploration of the Genetic Basis of Aflatoxin Biosynthesis

“…The AFPA is a selective media that identifies various Aspergillus species and gives the distinct characteristic color of many Aspergillus species especially A. flavus, A. parasiticus and A. niger. Many researchers have previously identified Aspergillus flavus using AFPA (Abriba et al, 2013;Fakruddin et al, 2015;Hossain et al, 2018). In the current study, one of the isolates was shown to be A. niger because it produced pale yellow to white hyphae, turning to dark brown to black on AFPA, which is in agreement to the previous results (Abriba et al, 2013).…”

“…On the reverse side of the AFPA culture plate, it also showed characteristics bright orange color. Though, AFPA was previously used for the identification of Aspergillus flavus (Hossain et al, 2018) yet the toxigenic potential is not usually determined by this media. While, to determine the toxigenic potential of A. flavus, APA media is used which shows a zone of toxin formation (in case of toxigenic fungus) under UV light (365nm).…”

“…Aspergillus spp. was identified and isolated on Aspergillus differentiation media (AFPA; M1127, HiMedia) as described earlier (Sekar et al, 2008;Abriba et al, 2013;Hossain et al, 2018).…”

“…The samples were analyzed on reverse-phase HPLC (Shimadzu, Kyoto, Japan) with a Discovery HS C18 column (Sigma-Aldrich, USA) equipped with a fluorescence detector (RF-530). Excitation and emission wavelengths were 360 and 440 nm, respectively (Gallo et al, 2012;Iqbal et al, 2013;Hossain et al, 2018).…”

“…Though individual work related to morphological and biochemical identification of Aspergillus sp. is available (Hossain et al, 2018), yet polyphasic approach of identification is rarely reported. In the current study, apart from molecular identification of A. flavus based on ITS-region, the isolated strain was also evaluated for the presence of two regulatory (aflR and aflS) and five structural (aflD, aflM, aflO, aflP, and aflQ) genes of aflatoxin biosynthesis within genetic cluster.…”