Development and characterization of food-grade tracers for the global grain tracing and recall system

Authors: LEE, KYUNG-MIN - Texas Agricultural Experiment Station; Armstrong, Paul; THOMASSON, ALEX - Texas A&M University; Sui, Ruixiu; Casada, Mark; HERRMAN, TIMOTHY - Texas Agricultural Experiment Station

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2010
Publication Date: 9/30/2010
Citation: Lee, K., Armstrong, P.R., Thomasson, A., Sui, R., Casada, M., Herrman, T.J. 2010. Development and characterization of food-grade tracers for the global grain tracing and recall system. Journal of Agricultural and Food Chemistry. 58:10945-10957. doi:10.1021/jf101370k

Interpretive Summary: Grain traceability is mandated by the Food and Drug Administration Bioterrorism Act of 2002. Achieving this in a commodity which is bulk handled and mixed with other sources of grain presents a significant challenge. Small pill-sized tracers, uniquely encoded and embedded in grain, are proposed as one method for grain traceability during handling and storage. To address the physical harshness of a grain handling environment, prototype tracers were manufactured and tested for physical strength properties. Tracer formulations and manufacturing processes were developed and used to produce tracers from food-grade starch, cellulose and sugar with different protective coatings. Components were chosen so that they would not be considered an adulterant to grain. Physical property tests were conducted on tracers to evaluate the relative strength of each formulation and the effect of moisture adsorption. In general all tracers were considered to have sufficient strength properties to withstand grain handling. Sugar based tracers were shown to be more susceptible to deterioration in humid environments and are considered less suitable than either the starch or cellulose based tracers. Protective coatings slowed moisture adsorption substantially and provided abrasion resistance. While still under development, this technology shows promise as a method to provide positive identification of grain.

Technical Abstract: Tracing grain from the farm to its final processing destination as it moves through multiple grain handling systems, storage bins and bulk carriers presents numerous challenges to existing recordkeeping systems. This study examines the suitability of coded caplets to trace grain; in particular, to evaluate methodology to test tracers’ ability to withstand the rigors of a commercial grain handling and storage systems as defined by physical properties using measurement technology commonly applied to assess grain hardness and end-use properties. Three types of tracers to dispense into bulk grains for tracing the grain back to its field of origin were developed using three food-grade substances (processed sugar, pregelatinized starch, and silicified microcrystalline cellulose (SMCC)) as a major component in formulations. Due to a different functionality of formulations, the manufacturing process conditions varied with for each tracer type, resulting in unique variations in surface roughness, weight, dimensions, and physical and spectroscopic properties before and after coating. The applied two types of coating (pregelatinized-starch and hydroxypropylmethylcellulose (HPMC)) using an aqueous coating system containing appropriate plasticizers showed uniform coverage and clear coating. Coating appeared to act as a barrier against moisture penetration, protect mechanical damage of the surface of the tracers, and improve the mechanical strength of tracers. The results of analysis of variance (ANOVA) tests showed the type of tracer, coating material, conditioning time, and a theoretical weight gain significantly influenced the morphological and physical properties of tracers. Optimization of these factors needs to be pursued to produce desirable tracers with consistent quality and performance when they flow with bulk grains throughout the grain marketing channels.