Evaluation of the Adsorption Efficacy of Bentonite on Aflatoxin M1 Levels in Contaminated Milk

The existence of aflatoxin M-1 (AFM(1)) in raw milk results in economic losses and public health risks. This research aims to examine the capability of bentonite to adsorb and/or eliminate AFM(1) from various raw milk types. In addition, the effects of numerous bentonites (HAFR 1, 2, 3 and 4) on the nutritional characteristics of the milk were studied. Our findings revealed that goat milk had the highest value of AFM(1) (490.30 ng/L) in comparison to other milks. AFM(1) adsorption was influenced by applying bentonite (0.5 and 1 g) in a concentration-dependent manner for different time intervals (from 0 to 12 h). The percentage of AFM(1) reached the maximum adsorption level after 12 h to 100, 98.5 and 98% for bentonites HAFR 3, 1 and 2, respectively. HAFR 3 (1 g bentonite) presented higher adsorption efficiency than other bentonites used in the phosphate buffer saline (PBS) and milk. Residual levels of AFM(1) reached their lowest values of 0 and 1.5 ng/L while using HAFR 3 in PBS and milk, respectively. With regard to the influence of bentonite on the nutritional characteristics of milk, there was an increase in fat, protein and solid non-fat ratio while using HAFR 3 and 4, yet decreased lactose in comparison with the control. Scanning Electron Microscopy and Fourier Transform-Infrared Spectroscopy both identified bentonites as superior AFM(1) binders. The results demonstrated that bentonite, particularly HAFR 3, was the most effective adsorbent and could thus be a promising candidate for the decontamination of AFM(1) in milk.