SBIR-STTR Award

The sterilization of powders and disinfestation of aggregates using existing technology present difficult product handling problems and often unacceptable economics. Ethylene Oxide is widely used for this purpose, while the alternate non-chemical (physical) processes of heat and gamma - radiation are expensive and frequently result in unacceptable damage to the product. The proposed program will provide a proof of principle demonstration of the practicability of using pneumatic transfer of these materials to present them in an efficient manner to low energy electron beams. These self-shielded energy sources can provide adequate beam power levels to provide very high throughputs. The present demonstration system will be utilized at under 3 kilowatts output and modest gas flow velocities (30-150 m/minute) with powder loading factors in the air stream of a few percent. The test will be conducted using both dose and the air stream powder loading factor as independent variables. The assembly and testing of the self-contained product handling system constitutes a major part of the program effort with the conduct of the experiments (including microbiological assays) representing a lessor part of the work. The remainder is in data processing and reporting. The objective is to demonstrate the efficacy of this physical process of known microbial challenge for powders aggregates at several stream loading factors so that industrial level designs can be made for processors in this voltage range 0.1-0.3 Mv) .Applications:Lethality data will be obtained for dried spores in the powder media selected. An evaluation of the dependence of lethality (effective D value) on stream loading will be ascertained to determine how close to the electron's effective range (in grams per square meter) one can load the air stream and still maintain confidence in the product treatment level/sterility assurance. Commercial applications are most promising in the disinfestation of stored agricultural products; e.g. animal feeds and their constituent ingredients. In particular, the elimination of E. coli, Salmonella tvphimurium and other vegetative bacteria, as well as yeasts and molds, in agricultural products offers a very large potential market. Treatment of cosmetic constituents represents a secondary market.

Phase I confirmed the "proof of principle" of electron beam irradiation of agricultural products when conveyed in a pneumatic stream. This fluid bed approach was shown to be as efficacious as the more expensive gamma ray treatment process for the control of natural aerobic bacteria and fungal populations. At present there are limited alternatives to chemical processes which as we learn more about their characteristics as ozone depleters, danger of application and toxic residues in food products, cause the usda and epa to call for their removal. Phase II then, will establish a service demonstration facility to allow modest levels of product processing, determine irradiation requirements and validate the satisfaction of those requirements for two commercial vendors, and to continue irradiation of selected grains and other agricultural products to optimize and further understand the process. We will complete the design of a mobile, self-shielded, low cost electron beam irradiation system and by the presentation of papers and contribution of articles to trade publications continue the education of those involved in united states agricultural products that a safer, economical, yet effective alternative to chemicals is available for treating a broad range of products.Applications:Results of this program will further confirm the advantages of electron beam irradiation of agricultural products to achieve disinfestation/sterilization. We believe as chemicals are further restricted that the market for "electron beam treaters" will be in the hundreds of millions of dollars for treatment of grains and fine powders, as it provides one of the few alternatives available to these industries.