Aflatoxin removal from contaminated foodstuffs by using the natural toxin binders

Aflatoxins (AFs) are a group of highly toxic secondary metabolites produced mainly by three Aspergillus species, including Aspergillus parasiticus, Aspergillus flavus, and Aspergillus nomius. The types of AFs presenting the most important public-health concerns are AFB1, AFB2, AFG1, and AFG2. The International Agency for Research on Cancer (IARC) has classified AFB1as a Group 1 human carcinogen. As a result, removal of AFs from foodstuffs is of great importance. The application of aluminosilicates has attracted enormous interest in AFs removal in preventing aflatoxicosis. It was reported that some aluminosilicates successfully bind AFs in vitro. In this study, five natural aluminosilicates were obtained from different regions in Iran (Hormak area, Sistan and Baluchestan province; Semnan province; East Azerbaijan province, Isfahan province, and Qom province). To evaluate the extraction efficiency of natural toxin binders, the rice samples were prepared and extracted with a mixture of methanol/distilled water (100 ml, 80/20 v/v; shaking, 30 min). During the removal procedure, 0.05 g of natural aluminosilicate was added into one ml of the filtrate solution and then the mixture was stirred (20 min). The concentration of AFs was determined using IAC-HPLC analysis, after separating the toxin binder/AFs complex and sampling from the liquid phase. Under optimized conditions, 35-100% of AFs were removed during 20 min. A 3-fold difference in AFs adsorption capacity was observed among these five natural aluminosilicates due to their large differences in aluminosilicates origin, the presence of functional groups, mineral composition, and charge density. The proposed procedure has also been compared with immunoaffinity column clean-up (IAC) method and a good correlation was found using natural zeolites and IAC method which indicated that the effectiveness of zeolites in adsorbing AFs.