Clay feed additives are marketed and sold in the United States as anti-caking agents to improve the physical properties of feed because U.S. Food and Drug Administration (FDA) regulations do not permit feed additive companies to claim that feed additives can bind mycotoxins and reduce mycotoxicoses. Therefore, feed additive companies have little financial incentive to develop additives with improved mycotoxin binding. Feed additives are mixed with dry feeds and, hence, mycotoxin binding to clays must occur after ingestion. During digestion, pH, feed composition, and other factors can affect mycotoxin binding to feed additives. Mycotoxin adsorption to feed additives can sequester the toxins and limit absorption by animals or humans. Feed additives that effectively remove mycotoxins from water, however, might not prevent toxicity to animals from contaminated feed because soluble feed or digestive compounds might block mycotoxin adsorption to feed additives.
Extensive research has shown that surface-modified clays (or organoclays) can more effectively remove organic contaminants from water than the untreated clays [28,29]. Organoclays prepared by