Mycobiota in Chilean chilli Capsicum annuum L. used for Merkén’s production and its mycotoxin contamination
In Chile, Capsicum annuum L. cv. "Cacho de Cabra” berry fruits are used for the manufacture of a traditional chilli powder known as Merkén. The agricultural practices used by Merkén local producers are empirical and do not consider the prevention of mycotoxigenic fungi and, in the last years, m...
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| Tipo de recurso: | tesis de maestría |
| Estado: | Versión publicada |
| Fecha de publicación: | 2018 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/218873 |
| Acceso en línea: | https://hdl.handle.net/10533/218873 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Naturales Otras Ciencias Naturales |
| Sumario: | In Chile, Capsicum annuum L. cv. "Cacho de Cabra” berry fruits are used for the manufacture of a traditional chilli powder known as Merkén. The agricultural practices used by Merkén local producers are empirical and do not consider the prevention of mycotoxigenic fungi and, in the last years, mycotoxin contaminations have been reported in Merkén. Therefore, the main goal of this study was to search for the potentially mycotoxigenic culturable mycobiota on the traditional agriculture production process of the Chilean traditional chilli used for Merkén’s production and search for mycotoxin contamination in Merkén produced and commercialised in Chile. Ripened fruit samples of C. annuum from 3 sampling point and Merkén samples were obtained from local farmers and markets of the South Zone of Chile. Mycobiota from ripened fruit were isolated on MEA, DRBC and DG18 media. Isolated fungal strains were identified using classical morphology and molecular biology techniques. For the classical taxonomy, macro- and micro-morphology traits where observed. For molecular identification of fungal strains sequencing of β-tubulin (BenA) and ITS (ITS1-5.8S-ITS2) were performed. In addition, genes associated with OTA production (Otapks, Otanps, Otachl and Otatra) were tested in one strain of P. crustosum and one strain of P. verrucosum. For the extraction and clean-up of ochratoxin A (OTA) and aflatoxins (AFLs) B1, B2, G1, G2, liquid-liquid extraction and immunoaffinity columns were performed. A total of 206 strains were obtained using classical macro- and micro-morphology. From these fungi, 190 were identified by molecular biology techniques at the species level. For genes associated with OTA production, P. verrucosum present positive results for Otanps and Otatra genes, and P. crustosum present positive results for Otatra gene only. For mycotoxins contamination of Merkén, OTA was presented in 100% samples in a range of 0.79±0.05 and 19.81±0.70 µg/kg and for AFLs, only AFB1 were detected in 57% samples in a range of 0.29±0.37 and 1.67±0.32 µg/kg. Overall, these results show that the mycobiota present in C. annuum berry fruits during the process of Merkén production is increasingly selective for occurrence of Aspergillus and Penicillium species, mainly for the increasingly selective occurrence of potentially mycotoxigenic fungi such as A. niger, A. flavus, P. expansum and P. verrucosum. These results demonstrate the importance of knowing even more about the mycobiota and potential mycotoxigenic fungi present in each stage used for the Merkén production, in order to establish critical control points for a safe and high-quality product. |
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