Wednesday, November 15, 2006 - 11:30 AM

Interfacing Clay Science with the Marketplace: An Aflatoxin Example.

Joe Dixon, Ines Kannewischer, and M.G. Tenorio-Arvide. College Station, TX 77843-2474, United States of America

The opportunities of clay research are well illustrated by the effectiveness of smectite clay to sorb one of the worst mycotoxins. Over the past two decades the use of smectite to suppress aflatoxin has been demonstrated for many animals; yet commercial marketing of smectite as a sorbent is stymied by legal constraints and doubt about clay performance. Our research has strengthened the view that smectite can be an effective suppressant in animal diets by the demonstrated associations within the galleries between clay layers. We believe that smectite can be a reliable sorbent for aflatoxin providing the clay meets certain analytical criteria. Natural clays are impure and are sometimes diverse in composition and properties. We have analyzed many smectites from different locations and found a ten-fold range in sorption capacity. Thus thorough analysis and sorption tests are required before they can be approved as feed additives. The state regulatory authority, Office of the Texas State Chemist has set action levels for aflatoxin in grains for the diets of particular animals. These action levels provide a working range (e.g. <100 ppb) and grains with aflatoxin below these levels can be amended with smectite to improve animal performance. Thus the consumer can decide how effective OTSC-approved smectite clays are at improving animal health and performance. Since commercial bentonites are processed in large batches sampling, analysis, and regulatory approval or rejection can be performed in advance of the need. Once labeled, the smectites can be marketed to feed mills for inclusion in feeds they mix and sell