Mississippi State University
Sparks, Darrell L., Jr.
Ward, Stephanie H.
Date of Degree
Dissertation - Open Access
Doctor of Philosophy
College of Agriculture and Life Sciences
Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology
Taking precautions to restrain aflatoxin M1 (AFM1) from milk is critical, particularly due to the health and economic impact AFM1 imposes. The predominant post-harvest means of reducing AFM1 in milk includes the addition of sequestering agents to feed to diminish the bioavailability of aflatoxin B1 (AFB1), the parent compound of AFM1 found in contaminated feed. Still, residual AFM1 has been found in the milk. Using sequestering agents added to raw milk, we found that activated carbon was the most effective binder to reduce AFM1 contamination. The combination of 0.75% granular activated carbon (GAC) and a flow rate of 0.4 mL/min to pump contaminated milk through a glass column were chosen as optimum conditions for the removal of AFM1. These conditions obtained a 98.4% reduction of 0.75 ng/mL AFM1 from raw milk. The treated milk was also analyzed to assess the effects of GAC on milk constituents. The results determined that GAC had no significant effect on major nutritive milk constituents: total protein, lactose, minerals, and fat. Additionally, we optimized an extraction method coupled to high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) that minimized matrix effects, lowered the levels of detection, and reduced analysis costs. The optimized extraction method was based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe). Results determined 5 mL milk (15°C) with 10 mL acetonitrile, 3200 g centrifugation, and 0.2 μm syringe filter were the optimum conditions for the extraction of 0.5 ng/mL AFM1 from raw milk. The method was validated according to AOAC guidelines. This study reports experimental results on AFM1 remediation from raw bovine milk. The use of GAC for the removal of AFM1 in raw milk has reduced the amount of AFM1 below the FDA action limit and European Union maximum regulatory level. This method could have a global health impact, particularly, for people in developing nations and for infants and children who are more susceptible to the adverse effects of AFM1.
Womack, Erika D., "The Evaluation of Adsorbents for the Removal of Aflatoxin M1 from Contaminated Milk" (2015). Theses and Dissertations. 4456.