Progress 05/01/05 to 12/31/06
Outputs
More than 400 million tons (15 billion bushels) of grain are stored every year in the United States. Insects and fungi create serious quality problems in stored grains, and annual storage losses are estimated at more than $500 million. These infestations not only cause physical degradation of the food; they also create ideal conditions for the post-harvest production and accumulation of mycotoxins, specifically the highly regulated aflatoxins. Further, numerous chemically-diverse mycotoxins may be present in the harvested grain prior to storage, thereby devaluing the grain and requiring the product to be blended, remediated, or destroyed. Some stored-product insects already exhibit some levels of phosphine resistance. In addition to this compounding problem, toxic phosphine residues create another health risk to the consumer and do not decontaminate mycotoxins, bacteria, or molds. An ideal broad spectrum treatment process would be low cost, non-toxic, non-residual, and
highly effective against a broad range of contaminants without the need for major renovations or altering the nutritional value of the commodity. In Phase I, Lynntech, Inc. developed a universal protective lab-scale processing protocol to fulfill these needs. The treatment method incorporated the use of electrochemically-generated ozone (O3) gas as the fumigating agent. The benefits of ozone in food safety have not gone unnoticed. Since its approval as a direct food additive for the treatment, storage, and processing of food in 2001, ozone has created a great deal of interest among academic researchers and food processors. The key challenges to the proper utilization of ozone gas are due to the physical and chemical characteristics of ozone gas: 1.Ozone is a highly reactive gas with a very short half-life in air (24 hours); 2.Ozone (O3) readily decomposes into oxygen (O2) which is accelerated by heat because the gas is temperature sensitive; 3.For corona discharge systems that do not
use (liquid or) gaseous oxygen as a feed gas, concentrations of ozone are very low - typically less than 2 wt%; 4.Its high reactivity means that in most engineered treatment systems - for water, solids, or air - the gas is quickly consumed by or catalytically destroyed by all molecules within the treatment matrix. The consumption of ozone by non-target molecules in any food or feed treatment system (i.e., grain pericarp, "fines", soil/clay particles, metal oxides/rust) are always in competition with the targets of the decontamination process (bacteria, insects and larvae, fungal spores and mycelia and their associated mycotoxins). Therefore, uniform delivery of gaseous ozone to food remains an engineering obstacle for development of proper ozone-based commodity treatment hardware. In Phase I, we have successfully advanced the development of a critical engineering design scenario by using aflatoxin destruction as the benchmark of successful ozone treatment in corn. Aflatoxin represents
a "worst case scenario" because it is the toughest, most challenging contaminants to address, when compared to bacteria and insects.
Impacts
This Phase I innovation provides stored crop protection by reducing the impact of plant pathogens, human pathogens, insect pests, storage molds, and harmful toxins by developing proven, efficient and environmentally safe pesticide alternative. By developing a dynamic ozone treatment test system, the Phase I project provided key insight into a pilot scale engineering design that would add value to post-harvest handling quality preservation of staple crops (corn, wheat, soy, canola, cottonseed) and potentially for specialty crops (amaranth, meadowfoam, nutraceutical herbs, spices). Importantly, the innovation provides an environmentally friendly alternative to other chemically persistent fumigants, in that ozone is easily broken down into harmless oxygen. By proving the comprehensive decontamination capability of ozone, the technical approach can be used as both a preventative fumigant for pre-storage treatment and as a remediation tool for chemically and/or biologically
contaminated grains and oilseeds.
Publications
- No publications reported this period
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Progress 05/01/05 to 08/31/05
Outputs
1. INTRODUCTION The overall objective of this research is to develop a uniform food decontamination step offering broad-spectrum, time and cost efficient decontaminating capabilities that will be safe to the environment and the operator. The ultimate aim of the Phase I research is to design and fabricate a flexible laboratory test system that can effectively and efficiently perform decontamination of a wide range of contaminants in raw grains. 2. DESIGN AND FABRICATION OF THE LABORATORY TEST SYSTEM In order to maintain homogenous ozonation and heat distribution, a system has been constructed to fluidize the test corn, circulate the ozone/air mixture through the test vessel, and determine the concentration and quantity of ozone in the system. 2.1. System Operation and Components The fluidization and ozonation system is capable of fluidizing 35 pounds of corn. A high pressure blower recirculates air and ozone through the corn in a stainless steel reactor. In order to
know the concentration and amount of ozone in the system, a sidestream is diverted from the main loop through a Gilmont rotameter and a Model 454 Ozone Monitor from the Advanced Pollution Instrumentation Division of Teledyne Instruments. 3. PRE-TREATMENT MICROBIOLOGICAL EVALUATION Microbiological recovery experiments were conducted on whole kernel corn purchased at a local feed supply store to determine the naturally-occurring bacterial and fungal flora and to test bactericidal effects of selected dyes used for visual identification of individual seeded kernels. 3.1. Characterization of Naturally-Occurring Microorganisms on Control Corn Four, 1 liter polyethylene containers with lids, previously cleaned with antibacterial soap, a dilute bleach solution, hot water and 70% ethanol, were allowed to air dry and 113.5 grams of shelled corn was added to each container. Sterile saline, 100mL, was added to two of the containers and 100mL of sterile saline + tween solution was added to the
other two containers. A total cell count was obtained at 24 hours and another at 48 hours. TSA and R2A plates were counted after 24 hours of incubation. After 48 hours of incubation, the plates were enumerated again. 3.2. Bactericidal Evaluation of Selected Food Dyes used for Visual Identification of Individual Seeded Kernels The purpose of this study was to identify a substance that would be non-toxic and allow staining of corn kernels so that seeded kernels could be distinguished from non-seeded kernels during post-treatment recovery. 3.3. Analysis of Aflatoxin-B1 in 2005 Post-Harvest Corn Samples Five corn samples, 4 yellow and 1 white, were collected from a local grain elevator and analyzed for aflatoxin B1 using a Vicam Aflatest System to determine if the lot would meet the high level criteria (>300 ppb AfB1) for the decontamination testing. About 70 bushels of the high concentration lots will be purchased and transported to Lynntech to initiate aflatoxin reduction experiments.
Impacts
N/A
Publications
- No publications reported this period
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