Enhance Aflatoxin Accessibility Into Smectite In Simulated Gastric Fluids.

Corn, peanuts and other crops can be invaded by Fungi Aspergillus flavus and Aspergillus parasiticus, which produce carcinogenic aflatoxins. The regulated maximum concentration of aflatoxins in food is 20ppb and between 20 – 300ppb for animal feeds. Among the aflatoxin decontamination techniques, incorporation of adsorbents in animal diet has been extensively investigated. In vitro experiments have demonstrated high aflatoxin adsorption capacities of bentonites (up to 20% of the clay’s mass), but poultry experiments showed large variations in chicken’s response. The clay’s in vivo effectiveness need to be enhanced. The objectives of this research were 1) to evaluate the simulated gastric fluid effect on the clay’s aflatoxin adsorption capacity, and 2) to evaluate the effect of clay dispersion methods on the aflatoxin adsorption. Single point aflatoxin concentration of 4.8ppm was used to compare clay adsorption in water and simulated gastric fluid (GF). Four clay treatments were used to compare the dispersion effect: 1) oven (60 °C) dried clay powder, 2) freeze dried clay powder, 3) sonicated clay suspension, and 4) anionic polymer stabilized clay suspension. Compared to the adsorption in water, aflatoxin adsorption in GF reduced by 33% to 61%, depending on the clay’s dispersion status.  Difference in adsorption could be due to GF’s acidic pH (4.8 in water and 3.3 in the simulated GF). Sonicated clay suspension showed the highest adsorption both in water (18.4% w/w) and GF (9.6% w/w). The polymer stabilized clay suspension and freeze dried clay were similar in adsorption in water, but in GF the freeze dry clay showed lower adsorption. Oven dry clay showed the lowest adsorption in both solutions (12.7% w/w in water and 5.3% w/w in GF). These results indicate that gastric fluid reduced the clay’s aflatoxin adsorption effectiveness in acidic condition. Higher adsorption of aflatoxin can be achieved by increasing the clay dispersion.