Progress 10/01/03 to 09/30/08
Outputs
OUTPUTS: In one of our projects, we continued to work on examining the relationship between mold feeding insects and mycotoxin transport within the stored grain ecosystem. In another project we expanded on our research to quantify the necessary engineering, entomological and economic parameters to make heat treatment of empty storage structures such as steel bins and tanks a successful control technique to prevent residual stored product pest populations from contaminating high-value identity-preserved food and specialty grains as well as conventional commodity grains and oilseeds. In a new project, we are addressing a major concern of growers, handlers and processors regarding insect infestation of high-value identity-preserved food and specialty grains (including organic grains) and processed grain products during container shipment. Currently there are few non-chemical alternatives for pest control in stored organic grains and grain-based products. One available technology that should be investigated and evaluated is nitrogen-based modified atmosphere. A full scale trial using bagged grain place in a shipping container study demonstrated that nitrogen treatment works. . It utilized a transportable nitrogen-based modified atmosphere treatment station.Initial tests were conducted using 0.71 cubic meter bags filled with soybeans. The bags were made from a five-layer plastic film that provided an oxygen barrier. They were purged with 99.9% nitrogen until the oxygen level was near zero. Stored product insect bioassays were placed inside the bags containing adult maize weevil, red flour beetle, lesser grain borer, and Indian meal moth adults and larvae. Bioassays were kept inside the nitrogen-purged bags for 3, 7, and 21 days. Results showed 100% mortality for all insects because oxygen level inside the bag was below 0.13% after 3 days of exposure, and a low concentration was maintained for 7 and 21 days. Maintaining a good seal on the bag, in addition to the proper selection of plastic film material, were essential contributors to success of the treatment. Preparing a larger bag for the 6.1 m long container was a substantial challenge. Nevertheless, preliminary trials with a shipping container using corn-filled tote bags and purged for 7 days with 99.9% nitrogen showed 100% mortality of RFB, MW and LGB adults. PARTICIPANTS: Purdue Staff: Dirk E. Maier, Professor of Ag & Bio Engineering; Richard L. Stroshine, Professor of Ag & Bio Engineering; Klein E. Ileleji, Assistant Professor of Ag & Bio Engineering; Linda J. Mason, Professor of Entomology; Corinne E. Alexander, Assistant Professor of Agricultural Economics; Charles P. Woloshuk, Professor of Botany & Plant Pathology; Dale Moog, Post-doctoral Research Associate, Ag & Bio Engineering; Carlos Campabadal, PhD Student, Ag & Bio Engineering; Wan-tien Tsai, PhD Student, Entomology; Partner Organizations: TempAir, Burnsville, MN; Fumigation Service & Supply, Indianapolis; O3Co, Aberdeen, Idaho TARGET AUDIENCES: Results of this research were presented at several national and international conferences (2006 International Working Conference on Stored Product Protection, Campinas, Brazil; 2006, 2007 Methyl Bromide Alternatives Conference; 2005, 2006, 2007, 2008 Annual Meeting of the Entomology Society of America; 2005, 2006, 2007, 2008 International Meeting of the American Society of Agricultural & Biological Engineers, 2008 International Grain Quality and Technology Congress, Chicago, USA; 2008 Controlled Atmosphere Conference, Chengdu, China), numerous extension workshops in Indiana, Illinois and Michigan, and industry conferences (2005, 2006, 2007, 2008 NC-213 Annual Technical Meeting; Illinois and Indiana Post Harvest Hands-on Training and Recertification Programs) attended by researchers, government regulators, and representatives of the U.S. grain handling and food processing industry as well as the pest control industry. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
A major contribution under objective 1 was the development of a system for early detection of mold growth in storage bins filled with shelled corn. This technology will enable timely action, such as withdrawal of a portion of the shelled corn that will preserve the quality of the remaining corn. Another contribution was the development of a simple test kit that permits assessment of shelled corn susceptibility to fungal invasion. The results of this relatively inexpensive 3-day test indicate the propensity for mold growth in the corn if conditions become conducive for such growth. Results can help facility managers decide which corn lots need to be utilized quickly and which can remain in storage or be shipped overseas where ambient conditions are favorable for mold development. Recent trends such as development of specialty and GMO varieties have increased the need for identity preservation. System simulations of identity preservation in grain handling facilities enabled various scenarios to be evaluated so that the most cost effective and efficient strategies could be identified. Major contributions under Objective 2 included development of methods for controlling insect pests without pesticides. They are needed because restrictions have been placed on pesticides such as methyl bromide and because there is a growing market for organic grain. Methods developed included heat treatment of storage and processing facilities and the use of nitrogen based modified atmospheres. In addition, studies of the interaction between grain storage insects and mold improved understanding of insect population dynamics. Finally, under objective 3, a distance learning program was developed in cooperation with other NC-213 institutions and the Grain Elevator and Processing Society (GEAPS). During the past three years, this successful University-industry partnership has enrolled 382 participants from 14 countries (including five Latin American countries) in a total of five courses offered ten times with a completion rate of 82%
Publications
- Moog, D.J.P., R.L. Stroshine, and L.M. Seitz. 2008. Relationship of Shelled Corn Fungal susceptibility to carbon dioxide evolution and kernel attributes. Cereal Chemistry 85(1):19-26.
- Chayaprasert, W., D.E. Maier, K.E. Ileleji, and J.Y. Murthy. 2008. Development and validation of Computational Fluid Dynamics models for precision structural fumigation. Journal of Stored Products Research 44 (2008) 11-20.
- Chayaprasert, W., D.E. Maier, K.E. Ileleji, and J.Y. Murthy. 2008. Effects of weather conditions on sulfuryl fluoride and methyl bromide leakage during structural fumigation in a flour mill. Accepted July 8, 2008 in Journal of Stored Products Research. (In press MS Ref No. SPR-D-08-00060R1).
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Progress 10/01/06 to 09/30/07
Outputs
OUTPUTS: In one of our projects, we are continuing to work on examining the relationship between mold feeding insects and mycotoxin transport with the stored grain ecosystem. Additionally, a new project was initiated that seeks to expand on our preliminary research and quantify the necessary engineering, entomological and economic parameters to make heat treatment of empty storage structures such as steel bins and tanks a successful control technique to prevent residual stored product pest populations from contaminating high-value identity-preserved food and specialty grains as well as conventional commodity grains and oilseeds. Heat treatment trials were conducted at the Purdue University Post-Harvest Education & Research Center (PHERC) in West Lafayette, Indiana and the Southeast Purdue Agricultural Center (SEPAC) located in Butlerville, Indiana. Two 30 ft diameter and 25 ft high bins were heat-treated using the burner of an in-bin drying system for SEPAC and the MHT 1500 heating
unit TempAir (Burnsville, MN) at PHERC. Before the start of the heat treatment, insect bioassays were prepared using PVC tubes. Species of adult maize weevils (MW), red flour beetles (RFB), and lesser grain borer (LGB) were used. Thirty insects were placed in each cage placed with either 300 grams of flour (for RFB), whole kernel corn (for MW), or wheat (for LGB). These cages were placed in the plenum and inside the augers near the door and away from the door. During the heat treatment using the in-bin dryer, the fan was covered halfway to restrict airflow through the bin and control of the burner was adjusted to provide inlet air close to 200oF. Temperature was monitored using twelve wireless sensors provided by TempAir and were placed in the three locations where the insect cages were placed and at four locations (North, East, South, and West) on the perforated floor and six feet above these points. The burner was turned off once the temperature inside the flour cage reached 130oF
(55oC). Cages were collected and left for 24 hours before sieving and counting the dead and live insects. The sieved materials from each insect cage were kept in separate bottles and were observed weekly for two months for possible insect re-emergence. For the PHERC bins, monthly insect population were monitored using dome traps and cardboard rolls placed inside the plenum. Heat treatment at 55oC (131oF) for three hours was sufficient for controlling the insects pests. The results of this study indicate that for heat treatment at any temperature, uniform distribution of the heated air has to be assured throughout the plenum. Additionally, the target temperature has to be reached and held sufficiently long to achieve 100% mortality.
PARTICIPANTS: Purdue Staff: Dirk E. Maier, Professor of Ag & Bio Engineering; Richard L. Stroshine, Professor of Ag & Bio Engineering; Klein E. Ileleji, Assistant Professor of Ag & Bio Engineering; Linda J. Mason, Associate Professor of Entomology; Corinne E. Alexander, Assistant Professor of Agricultural Economics; Charles P. Woloshuk, Professor of Botany & Plant Pathology; Dale Moog, Post-doctoral Research Associate, Ag & Bio Engineering; Carlos Campabadal, PhD Student, Ag & Bio Engineering; Wan-tien Tsai, PhD Student, Entomology; Partner Organizations: TempAir, Burnsville, MN;
TARGET AUDIENCES: Results of this research were presented at several national and international conferences (2006 International Working Conference on Stored Product Protection, Campinas, Brazil; 2006, 2007 Methyl Bromide Alternatives Conference; 2005, 2006 Annual Meeting of the Entomology Society of America; 2005, 2006, 2007 International Meeting of the American Society of Agricultural & Biological Engineers), numerous extension workshops in Indiana, Illinois and Michigan, and industry conferences (2005, 2006, 2007 NC-213 Annual Technical Meeting; Illinois and Indiana Post Harvest Hands-on Training and Recertification Programs) attended by researchers, government regulators, and representatives of the U.S. grain handling and food processing industry as well as the pest control industry.
Impacts
In one of our projects, we have examined development times and ovipositional preference of hairy fungus beetle (Typhaea stercorea (L.) Col: Mycetophagidae), when reared on pure cultures of Aspergillus flavus, Eurotium rubrum, and Penicillium purpurogenum, and the ability of hairy fungus beetle to develop in the presence of high levels of aflatoxin when fed A. flavus grown on coconut agar medium. Results indicate that hairy fungus beetle can complete its life cycle when fed these mold species grown on a defined medium in pure culture. Developmental times were shortest on A. flavus and longest on P. purpurogenum. Females appeared to prefer A. flavus as an ovipositional site resulting in more egg laying on cultures of A. flavus than on the other two species. Lastly, hairy fungus beetle can complete their life cycle in the presence of high levels of aflatoxin. The results suggested that the species of mold degrading grain can influence insect developmental rates and thus
population growth rates. In our new project, we are addressing a major concern of growers, handlers and processors regarding the contamination of high-value identity-preserved food and specialty grains (as well as conventional commodity grains and oilseeds) due to residual insect populations below the perforated floor (plenum) of corrugated steel farm bins (as well as tanks, silos and flat storage buildings at grain elevators) . Empty bin treatment with residual protectants such as inert diatomaceous earth dusts and cyfluthrin products have shown limited success because of the inherent inaccessibility of the plenum area. Similarly, the dousing of the perforated drying floor with cyfluthrin spray generally does not result in a uniform drip-through application of the hidden concrete floor and bin sidewalls. Disassembling the floor before filling a bin in order to clean and treat the plenum area is a labor-intensive and dangerous alternative. Fumigating under the floor is possible but is
costly. Chloropicrin (tear gas) has been the product of choice for under-the-floor fumigation of farm and elevator bins, but it is no longer available to licensed fumigators because the manufacturer will no longer allow shipment of small bottled product quantities through normal commercial channels. The use of phosphine as the only other legal fumigant product is generally limited to grain applications rather than empty bin treatment. Due to resistance concerns, it is primarily reserved for the control of primary stored product insect outbreaks above the economic threshold level in the grain mass. Therefore, a more effective method is needed to prevent contamination due to residual insect populations in empty bins. One such alternative is using heat to control insects and molds. Heat treatment of processing facilities and other structures to kill stored product pests is a widely used pest control technique.
Publications
- Ileleji, K.E., Maier, D.E. and Woloshuk, C.P. 2007. Evaluation of different temperature management strategies for suppression of Sitophilus zeamais (Motschulsky) in stored maize. Journal of Stored Products Research. 43:480-488.
- Tsai, W.T., L.J. Mason & C.P. Woloshuk. 2007. Effect of three stored grain fungi on the development of Typhaea stercorea. J. Stored Prod. Res. 43: 129-133.
- Weaver, D.K., G. E. Opit, L. J. Mason, & J. E. Throne. 2006. Gravimetric Method for Determining Stadia of Obligate Internally Feeding Stored-Product Insects. Environmental Entomology 35: 1483-1490.
- Bartosik, R.E. and Maier, D.E. 2007. Study of adsorption and desoprtion equilibrium relationships for three different corn types using the modified Chung-Pfost equation. ASABE Transactions. 50(5):1741-1749.
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Progress 10/01/05 to 09/30/06
Outputs
Progress on this project was made based on the need to improve grain quality, which has become ever more important as competition around the world increases and energy costs rise. The primary goals of this project were to (1) quantify the benefits of tempering on single kernel moisture content and stress crack development of corn using data collected in a small prototype continuous-flow dryeration (CFD) unit, (2) use the experimental results to modify and validate an existing computer simulation model in order to (3) scale-up and optimize the CFD system for a typical on-farm and elevator application, quantify energy savings and develop recommendations for future implementation. The experimental tempering results indicated that tempering reduced stress cracks up to 100% and moisture variability by 55 to 73% with the greatest reduction observed during the first four hours. Several concepts were presented that could be utilized for a full-scale continuous-flow dryeration
system. Commercially available hopper bins could be modified to incorporate a cooling section in the bottom and a tempering section in the top portion of the bin. Once validated, the cooler model was used to predict the moisture removal for a typical on-farm and elevator CFD system. The results indicated that the optimum elevator and on-farm applications removed up to 1.9 points of moisture from a hot grain moisture content of 17% (w.b.). It was also determined that the CFD system could reduce drying costs by up to 10.3% while increasing drying capacity by up to 36%.
Impacts
Based on the results of this research, continuous-flow dryeration systems could be designed and built to meet the growing needs of producers and elevator managers to increase drying capacity of existing systems while maintaining grain quality, and reducing drying costs and energy consumption.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
During the past two years, we determined the absorption and desorption equilibrium moisture content (EMC) relationship for corn with laboratory experiments, incorporated them into our PHAST-FDM model and quantified the hysteresis effect on drying simulation models. The EMC determines the moisture content to which grain can be dried under particular drying conditions. This relationship is of critical importance for grain drying studies. The Equilibrium Relative Humidity (ERH) determines the maximum interstitial air vapor pressure that can be reached given a certain moisture content of the stored grain, which is of critical importance for grain low temperature drying and storage studies. Our results from the 2003 drying season showed that our new self-adapting variable heat fan and burner control strategy did not show as good a control as expected with respect to avoiding the overdrying of the grain bottom layers in on-farm in-bin low temperature drying systems. Our
hypothesis was that the differences in the corn EMC relationship during the moisture desorption and absorption phases may have been more significant than previously assumed in the literature. To further explore the hysteresis effect on low temperature drying processes, a series of laboratory experiments were implemented. During the 2003 harvest season, samples of three different corn hybrids (yellow dent, white, waxy) with moisture content ranging from 20 to 22% were stored in the freezer. During the spring and summer 2004, these samples were divided to obtain two sets of sub-samples. One set of sub-samples was dried with natural air to 12% moisture content at laboratory conditions. Each one of the dry and wet sub-sample sets was further divided in 5 sub-sub-samples. The set of wet sub-samples was dried to 12, 14, 16, 18 and 20% moisture content (desorption samples). The set of dry sub-samples was rewetted to 12, 14, 16, 18 and 20% moisture content (absorption samples). Three
replicates of each sub-sub-sample was obtained and a series of EMC experiments at the typical drying temperature range for low temperature drying systems (from 5 to 30 C) was carried out in the lab in order to determine the EMC relationships. A second adsorption and desorption EMC/ERH was carried out with samples of yellow and white corn harvested during the 2004 drying season. The Modified Chung-Pfost equation using the 2003 set of parameters was validated with the 2004 EMC/ERH data. The main conclusions of this study were that the different corn types investigated had significantly different EMC/ERH relationships, that the adsorption and desorption relationships were different for each corn type, and that the prediction of EMC/ERH values using the current ASAE Standard set of parameters was significantly different compared to the white and waxy corn EMC/ERH data reported in this research.
Impacts
Based on the results of the EMC experiments, the absorption/desorption parameters for the Modified Chung-Pfost equation were estimated and incorporated into our PHAST-FDM model. They were also incorporated into a revised fan and burner control strategy and tested in five on-farm in-bin low temperature dryers during the 2004 harvest season with excellent results. The results will also be used to update a standard of the American Society of Agricultural and Biological Engineers.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/30/04
Outputs
During the past year, we determined the absorption and desorption equilibrium moisture content (EMC) relationship for corn with laboratory experiments, incorporated them into our PHAST-FDM model and quantified the hysteresis effect on drying simulation models. The EMC determines the moisture content to which grain can be dried under particular drying conditions. This relationship is of critical importance for grain drying studies. The Equilibrium Relative Humidity (ERH) determines the maximum interstitial air vapor pressure that can be reached given a certain moisture content of the stored grain, which is of critical importance for grain low temperature drying and storage studies. Desorption EMC is defined as the equilibrium moisture content that a product reaches after losing moisture. Absorption EMC is defined as the equilibrium moisture content that a relatively dry product reaches after taking up moisture from the environment. The EMC relationships for the
absorption and desorption processes are not the same. The desorption moisture content values are usually always higher than the absorption values. The difference is called the hysteresis effect. Our results from the 2003 drying season showed that our new self-adapting variable heat fan and burner control strategy did not show as good a control as expected with respect to avoiding the overdrying of the grain bottom layers in on-farm in-bin low temperature drying systems. Our hypothesis was that the differences in the corn EMC relationship during the moisture desorption and absorption phases may have been more significant than previously assumed in the literature. To further explore the hysteresis effect on low temperature drying processes, a series of laboratory experiments were implemented. During the 2003 harvest season, samples of three different corn hybrids with moisture content ranging from 20 to 22% were stored in the freezer. During the spring and summer 2004, these samples
were divided to obtain two sets of sub-samples. One set of sub-samples was dried with natural air to 12% moisture content at laboratory conditions. Each one of the dry and wet sub-sample sets was further divided in 5 sub-sub-samples. The set of wet sub-samples was dried to 12, 14, 16, 18 and 20% moisture content (desorption samples). The set of dry sub-samples was rewetted to 12, 14, 16, 18 and 20% moisture content (absorption samples). Three replicates of each sub-sub-sample was obtained and a series of EMC experiments at the typical drying temperature range for low temperature drying systems (from 5 to 30 C) was carried out in the lab in order to determine the EMC relationships. The methodology that was used to determine the EMC relationship was proposed and described by Chen and Morey (1989).
Impacts
Based on the result of the EMC experiments, the absorption/desorption parameters for the Modified Chung-Pfost equation were estimated and incorporated into our PHAST-FDM model. They were also incorporated into a revised fan and burner control strategy and tested in five on-farm in-bin low temperature dryers during the 2004 harvest season with excellent results.
Publications
- Singh, P.P., Maier, D.E., Cushman, J.H., Haghighi, K., Corvalan, C. 2004. Effect of viscoelastic relaxation on moisture transport in foods. Part I: Solution of general transport equation. Journal of Mathematical Biology. Published online 2 January 2004. ARP No. 17119.
- Singh, P.P., Maier, D.E., Cushman, J.H., and Campanella, O.H. 2004. Effect of viscoelastic relaxation on moisture transport in foods. Part II: Sorption and drying of soybeans. Journal of Mathematical Biology. Published online 2 January 2004. ARP No. 17120.
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