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Alemayehu S, Abera FA, Ayimut KM, Darnell R, Mahroof R, Harvey J, Subramanyam B. Effects of Storage Duration and Structures on Sesame Seed Germination, Mold Growth, and Mycotoxin Accumulation. Toxins (Basel) 2023; 15:39. [PMID: 36668858 PMCID: PMC9861261 DOI: 10.3390/toxins15010039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/23/2022] [Accepted: 03/29/2022] [Indexed: 01/05/2023] Open
Abstract
Sesame is an important oil crop for the Ethiopian economy. However, the lack of adequate storage facilities results in significant losses of sesame seeds. This study was designed to compare the effects of storage conditions and the subsequent impact on sesame seed germination, mold growth, and mycotoxin accumulation over the storage period. The efficacy of two hermetic bags (1. Purdue Improved Crop Storage (PICS) bags and 2. Super GrainPro (SGP) bags) was directly compared to sesame storage in polypropylene (PP bags) and Jute bags. Storage conditions (oxygen, carbon dioxide, temperature, moisture content and relative humidity) of samples were analyzed in the laboratory in three replicates. Results showed that the oxygen concentrations dropped to 6.9% (±0.02) in PICS bags and 8.7% (±0.06) in SGP bags at the end of 6 months of storage. In non-hermetic bags Jute and PP), oxygen levels were close to atmospheric levels at 2-, 4-, and 6-month storage periods. In non-hermetic bags throughout storage, the amount of seed infection by mold constantly increased, and seed germination decreased. Sesame seeds stored in hermetic bags had 89.7% (±0.58) to 88.3% (±2.89) germination rates versus 61.67% (±2.08) for non-hermetic storage bags over the 6-month seed storage period. All mycotoxin levels increased over the same storage period, whereas comparative levels were much lower in hermetic bags after six months. Sesame seeds stored in both hermetic bags had the lowest level of tested mycotoxins, and levels among the SGP and PICS bags were not significantly different from one another. This study provides strong evidence indicating that hermetic storage structures such as PICS and SGP significantly affect temperature, humidity, moisture content, CO2 and oxygen levels resulting in the lowering of fungal growth and mycotoxin accumulation and effectively preserving stored sesame without relying on synthetic pesticides in Ethiopia.
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Affiliation(s)
- Samuel Alemayehu
- Department of Biology, College of Natural and Computational Sciences, Mekelle University, Mekelle P.O. Box 231, Tigray, Ethiopia
| | - Fetien Abay Abera
- Department of Dryland Crop and Horticultural Sciences, College of Dryland Agriculture and Natural Resources, Mekelle University, Mekelle P.O. Box 231, Tigray, Ethiopia
| | - Kiros Meles Ayimut
- Department of Dryland Crop and Horticultural Sciences, College of Dryland Agriculture and Natural Resources, Mekelle University, Mekelle P.O. Box 231, Tigray, Ethiopia
| | - Ross Darnell
- Commonwealth Scientific and Industrial Research Organization, P.O. Box 2583, Brisbane 2601, Australia
| | - Rizana Mahroof
- Department of Biological and Physical Sciences, South Carolina State University, Orangeburg, SC 29117, USA
| | - Jagger Harvey
- Feed the Future Innovation Lab for the Reduction of Post-Harvest Loss, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA
| | - Bhadriraju Subramanyam
- Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA
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Ajmal M, Alshannaq AF, Moon H, Choi D, Akram A, Nayyar BG, Gibbons JG, Yu JH. Characterization of 260 Isolates of Aspergillus Section Flavi Obtained from Sesame Seeds in Punjab, Pakistan. Toxins (Basel) 2022; 14:toxins14020117. [PMID: 35202144 PMCID: PMC8876583 DOI: 10.3390/toxins14020117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 11/16/2022] Open
Abstract
Sesame Sesamum indicum L. is a major oil-based seed crop that has been widely cultivated and consumed in Pakistan. Unfortunately, sesame is highly prone to Aspergillus fungal growth in the field, and under inappropriate storage conditions can become contaminated with aflatoxins, the most potent carcinogen found in nature. Here, we have isolated a high number of Aspergillus isolates from sesame seeds in fresh and stored conditions obtained from rainfed and irrigated zones of Punjab, Pakistan, and characterized them for aflatoxigenic potentials. Using morphological identification techniques, 260 isolates were grouped as potential Aspergillus section Flavi, with 126 and 134 originating from the rainfed and irrigated zones, respectively. Out of 260 in total, 188 isolates were confirmed to produce aflatoxins. There were no significant differences in potential aflatoxigenic isolates with respect to the rainfed and irrigated zones. However, the number of potential aflatoxigenic isolates was significantly higher (p < 0.05) in stored samples than that of those from fresh sesame seeds in the rainfed and irrigated zone. Whole genome sequencing and comparative analyses of 12 select isolates have revealed that one of the A. flavus isolates, which produced very low aflatoxins (AFP10), has an elevated missense variant rate, numerous high impact mutations, and a 600 base pair deletion in the norB gene. In summary, our study provides insights into aflatoxigenic potential and the associated genetic diversity of indigenous Aspergillus section Flavi isolates and potential management strategies for reducing aflatoxin contamination levels in a major crop consumed in Punjab, Pakistan.
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Affiliation(s)
- Maryam Ajmal
- Department of Botany, Faculty of Sciences, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi 46300, Pakistan; (M.A.); (A.A.)
| | - Ahmad F. Alshannaq
- Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA; (A.F.A.); (H.M.); (D.C.)
| | - Heungyun Moon
- Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA; (A.F.A.); (H.M.); (D.C.)
| | - Dasol Choi
- Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA; (A.F.A.); (H.M.); (D.C.)
| | - Abida Akram
- Department of Botany, Faculty of Sciences, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi 46300, Pakistan; (M.A.); (A.A.)
| | - Brian Gagosh Nayyar
- Department of Botany, Faculty of Sciences, University of Sialkot, Sialkot 51310, Pakistan;
| | - John G. Gibbons
- Department of Food Science, College of Natural Sciences, University of Massachusetts, Amherst, MA 01003, USA;
| | - Jae-Hyuk Yu
- Department of Bacteriology, Food Research Institute, University of Wisconsin-Madison, 1550 Linden Drive, Madison, WI 53706, USA; (A.F.A.); (H.M.); (D.C.)
- Department of Systems Biotechnology, Konkuk Institute of Science and Technology, Konkuk University, Seoul 05029, Korea
- Correspondence:
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