Grant Information
| Knowledge Area | Subject of Investigation | Field of Science | Percent |
|---|---|---|---|
| 211 - Insects, Mites, and Other Arthropods Affecting Plants | 1510 - Corn (for sweetcorn use 1480) | 1130 - Entomology and acarology | 50% |
| 711 - Insects and Other Pests Affecting Humans | 1510 - Corn (for sweetcorn use 1480) | 1102 - Mycology | 50% |
Corn is vitally important to the US agricultural and food economies, and ensuring a sustainable supply of quality corn is critical in the years to come; not only for the United States, but for the global food supply. Insect invasion and mycotoxin contamination due to mold growth during post-harvest storage cause significant loss of stored grains and is extremely harmful to human and animal health. Different conventional techniques are in practice to control insect and mold of stored grains. Mostly practiced conventional methods are sanitation of storage bins/containers, fumigation using EPA permitted pesticides and fungicides, maintaining low storage temperature moisture in the storage bin. Fumigation using synthetic pesticides and fungicides are hazardous to environment and human health and most of the fumigants used in conventional cereal grain protection, cannot be used for organic grains. With increasing demand of organic corn grains as both food and feed, using non-toxic phytochemicals as fumigants may be a good approach to protect organic grains from insect damage and mycotoxin contamination during storage. Therefore, the goal of the proposed project is to control insect damage and mold growth in stored corn grains using non-toxic natural products as alternative to replace toxic fumigants, thus reducing food loss and mycotoxin accumulation during storage, and protecting human and animal health.
The goal of the proposed project is to control insect damage and mold growth in stored corn grains using non-toxic natural products as alternative to replace toxic fumigants, thus reducing food loss and mycotoxin accumulation during storage, and protecting human and animal health. Therefore, the proposed project will address NIFA's two important priorities: 1. Food Security and 6. Food Safety, and CAES's new research cluster: Enhancing Food Safety, Nutrition and Health.Specific objectives of this proposed integrated project are to:
The project is dealing with the corn grain storage insects, molds and mycotoxins because insects damage and mold/mycotoxin contamination cause grain loss, and couldcause serious food safety problem. An interdisciplinary approach including food chemistry, entomology and mycology will be needed to accomplish the project objectives. The insecticidal activity of essential oil, GSE and PSE will be contacted in entomology lab, and fungicidal activity will be conducted in microbiology lab and mycotoxin quantification will be conducted in food chemistry lab.The organic corn grains and 6 essential oils (EOs) will be purchased from the commercial suppliers, GSE and PSE will be extracted from grape seeds and peanut skin in food chemistry lab, freeze dried and stored at -20°C. The chemical composition of essential oils and GSE/PSE will be determined by GC and HPLC or LC-MS, respectively. The insecticidal and fungicidal activities of single EOs, GSE and PSE will be conducted simultaneously using small corn samples (25g) to evaluate the effectiveness of each EO, GSE and PSE against maize weevil and the specific mold and mycotoxin at different concentrations. The insecticidal activity of EOs will be conducted by simulated fumigation in glass containers containing corn grains and maize weevils, and expressed as concentrations causing 50% and 90% insect death (CL50 and CL90). The insecticidal activities of GSE and PSE will be tested by direct contact method and expressed as concentrations causing 50% insect death CL50.The fungicidal activity of each EO will be determined by both direct contact method and simulated fumigation methods, and the fungicidal activities of GSE/PSE will be determined by direct contact methods using sterile corn grains and known fungi. Six fungal genera including Aspergillus flavus, A. niger, Fusarium graminearum, F. verticillioides, Penicillium oxalicum and P. chrysogenum will be tested. The antifungal activity six EOs will be measured number of mold colonies and specific mycotoxin content of each treated corn sample. Major mycotoxins including Aflatoxin B1 (AFB1), zearalenone (ZEA), deoxynivalenol (DON), fumonisin B1 (FB1) and ochratoxin A will be determined by HPLC method. Data will be compared by Duncan's Multiple Range Comparison Test to obtain the most effective EO for each fungi genera.The mixtures of two effective EOs and EO with GSE/PSE at different ratios (25/75, 50/50/75/25) will be tested with corn grains for their synergies in insecticidal and fungicidal activities will be evaluated. There will be a synergy between two EOs or EO with GSE/PSE if the weevil survival rate, mold growth or mycotoxin content significantly lower than those at single EO or single GSE or PSE alone at 5% significance level. The optimal concentrations of EO, GSE, and PSE or the combination of EOs, EO-GSE, EO-PSE PSE will be used in the antifungal activity studies in large quantity of organic corn grains (2kg per treatment) and the extracts will be tested against naturally occurred molds and mycotoxins. The results obtained will be compared with both negative control (untreated grains) and positive control grains (the sample treated with a commercial fungicide for organic corn grains).
Target Audience
Grain farmers, agricultural extension agents, scientists and quality control managers in food and feed industry, researchers in cereal sciences and food science and food safety officials.
Changes / Problems
Major problems or delays: Due to COVID-19 pandemic, the labs were lockdown from March 15 to June 22. The lab in the Center of Excellence for Post-Harvest Technology was not reopen until July 6, 2020. During this period, only limited research was conducted. After reopening, the research activity was slower than planned in the proposal because of the social distance issue. Due to the pandemic and social distance issues in the lab, there was no undergraduate students to participate in the project activity. Significant deviations from research schedule or goals: Since March 15,2020, graduate students were required to work on thesis writing due to lab lockdown and limited access to the lab. Both graduate students completed their literature review parts of the thesis. In addition, we conducted the research activities based on what we could do under current condition/situation, not according to the approved Timeline in the proposal. The chemical compositions of essential oils used in the research were obtained from literatures, not by GC analysis because the collaborator who is responsible for chemical composition analysis retired right after the project started, and the new personnel in charge of the analytical lab does not know how to operate GC.
Training & Professional Development
Three graduate students have been involved in the project. Sawo Eesiah has been trained to test the anti-insect potential of essential oils (EOs) as her thesis research. She has been trained to test the anti-insect activity of 5 EOs and she will select two most effective EOs to test their synergy. Ivana Ramos Pedroso was trained to conduct anti-fungal activity of essential oils which will be her thesis research. She has been trained with experimental design, mycotoxin extraction, and purification. Both of them are under training to write thesis and make presentations. Rabiatu Bonku was a continued graduate student. She was supported by this project for 2 semesters and involved in this project by helping Sawo Eesiah in terms of data collection, calculation and graphing.
Dissemination Streams
The results of anti-insect activity of different essential oils were virtually disseminated at CAES student showcase. Due to COVID-19 pandemic, other events for dissemination such as 2020 Small Farms Week and 2020 Small Farm Field Day were canceled. We submitted abstracts to The Southwest & Southeastern Regional Meeting of the American Chemical Society scheduled on October 15-16, 2020 in New Orleans. However, the meeting was canceled about one week before the scheduled meeting date due to the pandemic. We recently submitted three abstracts to IFT 2021 Annual Meeting and Food Expo. We also plan to disseminate the research findings in 2021 Small Farms Week and 2021 Small Farm Field Day, and other conferences either virtually or in person if possible.
Next Reporting Steps
During the next reporting period, the team plans to complete the rest part of objective 2 (study the impacts of single EOs, PSE and GSE on insect mortality and oviposition in the corn grains), objective 3 (evaluate the effect of single EO, GSE and PSE on mold growth and mycotoxin production) and part of the objective 4 (study the synergies among EOs, between EO and GSE/PSE against storage insects, molds and mycotoxins). However, we may be unable to test and anti-insect and antifungal activities of GSE (grape seed extract) and PSE (peanut skin extract) due to the problems/issues below.