Effects of Storage Duration and Structures on Sesame Seed Germination, Mold Growth, and Mycotoxin Accumulation

Samuel Alemayehu; Fetien Abay Abera; Kiros Meles Ayimut; Ross Darnell; Rizana Mahroof; Jagger Harvey; Bhadriraju Subramanyam

doi:10.3390/toxins15010039

Effects of Storage Duration and Structures on Sesame Seed Germination, Mold Growth, and Mycotoxin Accumulation

Toxins (Basel). 2023 Jan 4;15(1):39. doi: 10.3390/toxins15010039.

Authors

Samuel Alemayehu¹, Fetien Abay Abera², Kiros Meles Ayimut², Ross Darnell³, Rizana Mahroof⁴, Jagger Harvey⁵, Bhadriraju Subramanyam⁶

Affiliations

¹ Department of Biology, College of Natural and Computational Sciences, Mekelle University, Mekelle P.O. Box 231, Tigray, Ethiopia.
² Department of Dryland Crop and Horticultural Sciences, College of Dryland Agriculture and Natural Resources, Mekelle University, Mekelle P.O. Box 231, Tigray, Ethiopia.
³ Commonwealth Scientific and Industrial Research Organization, P.O. Box 2583, Brisbane 2601, Australia.
⁴ Department of Biological and Physical Sciences, South Carolina State University, Orangeburg, SC 29117, USA.
⁵ Feed the Future Innovation Lab for the Reduction of Post-Harvest Loss, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506, USA.
⁶ Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506, USA.

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.

Keywords: Ethiopia; fungal growth; germination; hermetic bags; moisture content; mycotoxin; sesame seed.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Fungi
Germination
Mycotoxins* / analysis
Oxygen
Seeds / chemistry
Sesamum*

Substances

Mycotoxins
Oxygen

Grants and funding

This work was supported by the American people through the United States Agency for International Development (USAID) under the Feed the Future initiative (www.feedthefuture.gov) with grant number AID-OAA-L-14-00002. The contents are the responsibility of the Innovation Lab for the Reduction of Post-harvest Loss (www.k-state.edu/phl) and do not necessarily reflect the views of USAID or the United States Government.