Green synthesis of okra mucilage-capped iron oxide nanoparticles and their application for aflatoxin M1 reduction in buffalo milk

Abstract Aflatoxin M1 contamination of milk is a significant public health concern particularly in high-fat milk products like buffalo milk where traditional detoxification may affect nutritional quality. The present study aimed to assess the magnetic removal of AFM1 from raw buffalo milk by a green synthesis process with okra mucilage-coated iron oxide nanoparticles. The nanoparticles were synthesized at four different concentrations of the iron precursors (2, 5, 8, 10 mM) and characterized using UV–Vis spectroscopy, Fourier Transform Infrared Spectroscopy and X-ray Diffraction. The 5 mM formulation resulted in the most crystalline and monodispersed hematite (α-Fe2O3) nanoparticles and the most effective detoxification. The optimized nanoparticles were applied to five naturally contaminated buffalo milk samples with 0.92 to 5.15 μg/L AFM1, and the toxin reduction was found to be 98.53% after 60 min and 89.3% after five reuses. Significantly, treatment did not affect the milk physicochemical properties and the carryover of residual iron was negligible. Precursor concentrations below and above the optimized value were less effective due to low yield of nanoparticles or agglomeration. Based on these results, it can be concluded that OM-IONPs are a potential, scalable and food-safe magnetic nano-adsorbent for efficient AFM1 removal in the dairy industry.