الفهرس 
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Abstract
This study investigated aflatoxin M1 (AFM1) residues in milk and some dairy products as well as applying advanced procedures for AFM1 detoxification in lab-manufactured yoghurt. ELISA was used to estimate AFM1 in 105 samples of processed cheese, Ras cheese, and raw milk samples (35 of each) collected randomly from the Egyptian markets. Nearly half of the positive samples were tested using high-performance liquid chromatography (HPLC) with fluorescence detection for comparing the degree of sensitivity and accuracy of ELISA and HPLC methods. Mold count was determined in the analyzed samples with referring to AFB1 concentration using HPLC. Results revealed that AFM1 was detected in all tested Ras cheese, raw milk, and 82.86% of processed cheese samples with mean values of 51.05 ± 6.19, 40.27 ± 3.99, and 10.77 ± 1.39 ng/kg, respectively. There was no significant difference in AFM1 levels between the core and the crust parts of Ras cheese samples. Additionally, About 48.57 and 25.71% of the examined Ras cheese and raw milk samples exceeded the Egyptian standard levels (50 ng/kg). Comparing with HPLC approach, samples examined by ELISA revealed acceptable correlation with non-significant difference (P˃0.05). Alternatively, none of the examined samples proved to be contaminated with AFB1 despite the presence of mold with mean counts of 3.79 ± 3.29, 4.39 ± 4.34, and 4.84 ± 4.29 log cfu/g or ml in examined processed cheese, Ras cheese, and raw milk samples, respectively. In the second phase of the study, different viable, acid and heat treated probiotics of Bifidobacterium bifidum, Lactobacillus acidophilus, Bacillus subtilis, Lactobacillus plantarum, and Saccharomyces cerevisiae strains were evaluated for their effect on AFM1 reduction in simulated yoghurt model separately and in mixture during two weeks of storage period. Moreover, the probiotic presented the highest AFM1 reduction% was used for nano-encapsulation with chitosan-sodium tripolyphosphate (C-ttp-B) and chitosan-CaCl2-alginate (Cs-c-Ag-B) to evaluate their impact on AFM1 reduction. All studied probiotics could reduce AFM1 efficiently when compared with yoghurt starter culture (P<0.05), the highest efficacy was regarding L. acidophilus. The percentage of AFM1 reduction achieved by parabiotics was higher than that of probiotics. Furthermore, the bacterial/yeast combination (L. acidophilus-B. bifidum- S. cerevisiae) scored the best AFM1 reduction when compared with the single treatments, with reduction percentage of 89.58% by the acid-treated co-culture. Nano-encapsulated L. acidophilus with (Cs-c-Ag-B) and (C-ttp-B) achieved fast significant reduction of 68.09 and 80.57%, respectively, on the first day of yoghurt storage. These findings give safe and effective solutions for AFM1 control in