The Role of Probiotic Bacteria in Protecting against Aflatoxin M1 Contamination in Milk and Certain Dairy Products

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Abstract
Purpose:The present study investigated AFM1 contamination in raw milk, kareish cheese and yoghurt and studied the abilities of heating and probiotic bacteria to reduce AFM1 contamination in both raw milk and yoghurt. Methods: AFM1 was detected in raw milk in 10 of 12 samples (83.3%) from each season. Two methods were used to assess the toxigenic potential. HPTLC was performed for aflatoxin detection. Aflatoxin M1 contamination milk and selected dairy products was investigated against heating and Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 and its combination. Result: Cheese had the highest mean values concentration of AFM1 (527.4 and 651.3 ng/kg), and yoghurt had the lowest concentration (39.13 and 64.68 ng/kg) while, raw milk samples were (207.0 and 311.8 ng/kg) during summer and winter, respectively. The concentration of toxin in 83.33% of the examined cheese samples exceeded the EU limit (50 ng/kg), and 70.83% of these samples exceeded the Codex limit (500 ng/kg) during both seasons. Boiling degraded 26.71% of the AFM1. Whereas, pasteurization only degraded 15.45%. In yoghurt, two strains of probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium lactis) each gradually reduced the AFM1 concentration as a function of time in milk contaminated with 25 ng/l, with complete elimination by the end of the refrigerated storage period (3 days), while, the combination of both probiotic bacteria (L. acidophilus and B. lactis) was better able to reduce AFM1 in milk contaminated with 50.0 ng/kg or 75 ng/kg AFM1.Conclusion: The most extensive reductions of the AFM1 concentration were to 41.80 ng/kg (45.3%), 22.6 ng/kg (69.90%) and 7.12 ng/kg (92.8%), which were achieved using the same concentration of each strain individually and in combination, respectively, after two days in milk contaminated with 75 ng/kg. No AFM1 was detected after three days using the combined strains.

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