Fungal Contamination and Mycotoxin Production by Aspergillus Spp. In Nuts and Sesame Seeds

Abstract

This work reports the occurrence of the fungal flora and evaluates the mycotoxigenic potential of Aspergillus genera in 63 samples of oil seeds and nuts (almonds, pistachio and sesame seeds). Fungal isolation and identification revealed the presence of 5 genera (Aspergillus, Penicillium, Cladosporium, Mucor and yeasts) with the predominance of Aspergillus section Nigri. A number of 138 strains of Aspergillus section Nigri and 91 of Aspergillus section Flavi were isolated and tested for their ability to produce ochratoxin A (OTA) and Aflatoxin, respectively. The detection of Aflatoxins and OTA production was carried out using thin-layer chromatography (TLC). Our results showed that 93.93% of Aspergillus carbonarius were able to produce OTA, but none of the Aspergillus niger aggregate was found to be an OTA-producer. Among the 91 Aspergillus section Flavi isolates, 88 were identified as Aspergillus flavus and 3 as Aspergillus parasiticus. All A. parasiticus were strong AFB and AFG producers. A percentage of 30.3% of A. flavus isolates produced AFB1, with levels ranging from 0.69 to 44.28 μg.g−1. The frequency of aflatoxigenic A. flavus strains was higher in pistachios (46.3%) than in almonds (30.3%) or sesame seeds (23.52%). Cyclopiazonic acid (CPA) and sclerotia production were carried out on CYA medium. All aflatoxigenic A. flavus strains produced CPA, whereas 29.2% produced sclerotia (L-type).

Usage UV Irradiation for Reducing Fungal Contamination of Loose Nuts in Al Jouf Markets

“…These results are matched with previous studies that isolate and diagnose some fungi from nuts which offered for human usages such as Rhizopus spp, A .niger, Penicillium spp, Rhizoctonia spp, Chaetomium spp, Trichoderma spp and Fusarium spp (AL-Rawi , 2009). Our results are in good agreement with the study results of Mimoune (2016) who showed that Aspergillus sp. and Penicillium sp.…”

Polyphasic characterization of Aspergillus section Flavi isolated from animal feeds in Algeria

“…In this study, chemotypes II (produce more AFB2 than AFB1), chemotype III (producers of AFB but not CPA) and chemotype VI (producers of AFB, AFG, and CPA) were not found. The same results were reported in Algeria by Ait Mimoune et al () and Riba et al (). The incidence of non‐aflatoxigenic isolates representing chemotype V that was found in our study is relatively low (6.4%) in comparison with results reported by other authors (Razzaghi‐Abyaneh et al, ; Rodrigues et al, ; Sánchez‐Hervás, Gil, Bisbal, Ramón, & Martínez‐Culebras, ; Vaamonde et al, ).…”

“…Based on this identification, A. flavus strains were the predominant (78.5%), followed by 19.2% of A. tamarii , 1.7% of A. parasiticus , and 0.6% of A. alliaceus . The dominance of A. flavus have been reported in other commodities from Algeria such as wheat and wheat products (Riba et al, ), dried fruits (Ait Mimoune et al, ), peanuts (Guezlane‐Tebibel et al, ), and spices (Azzoune et al, ). Similar results were shown in other African countries like Tunisia for cereals (Jedidi et al, ; Jedidi, Cruz, González‐Jaén, & Said, ), and Tunisian vineyards (Melki Ben Fredj et al, ), Morocco for wheat grains (Hajjaji et al, ) and Nigeria for maize and marketed poultry feed (Atehnkeng et al, ; Ezekiel, Atehnkeng, Odebode, & Bandyopadhyay, ).…”

“…All sclerotia produced by the A. flavus isolates were dark, hard with nearly spherical shape (globose to subglobose), and were larger than 400 μm (L strains). Many studies reported the dominance of the L strains from Algeria (Ait Mimoune et al, ; Guezlane‐Tebibel et al, ; Riba et al, ), Nigeria ( Atehnkeng et al, ; Ezekiel et al, ; Ezekiel et al, ), Italy (Giorni et al, ), Portugal (Rodrigues, Santos, Venâncio, & Lima, ; Rodrigues, Venâncio, Kozakiewicz, & Lima, ), Argentina (Astoreca, Dalcero, Fernández Pinto, & Vaamonde, ), Brazil (Baquião et al, ), and several Sub‐Saharan countries in Africa (Probst, Bandyopadhyay, & Cotty, ). While others reported that S strain isolates were frequently found in high‐temperature regions with relatively low rainfall like in Eastern Kenya (Okoth et al, ; Probst, Bandyopadhyay, Price, & Cotty, ; Probst, Schulthess, & Cotty, ), and North America (Cardwell & Cotty, ).…”

“…To the best of our knowledge, the incidence of Aspergillus section Flavi in animal feeds in Algeria is relatively unknown, although a few studies were conducted on wheat (Riba et al, ; Riba, Mokrane, Florence, Lebrihi, & Sabaou, ; Zebiri et al, ), nuts (Guezlane‐Tebibel, Bouras, Mokrane, Benayad, & Mathieu, ; Riba, Matmoura, Mokrane, Mathieu, & Sabaou, ), spices (Azzoune et al, ), and dried fruits (Ait Mimoune et al, ; Ait Mimoune, Riba, Verheecke, Mathieu, & Sabaou, ). Thus, the present investigation aimed to identify Aspergillus section Flavi species isolated from animal feeds and their corresponding raw materials (maize, soybean, wheat bran, and barley) using a polyphasic approach which involved morphological, chemical, and molecular methods, and to evaluate their distribution and toxigenicity potential.…”