Purpose:The present study investigated AFM 1 contamination in raw milk, kareish cheese and yoghurt and studied the abilities of heating and probiotic bacteria to reduce AFM 1 contamination in both raw milk and yoghurt. Methods: AFM 1 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 M 1 contamination milk and selected dairy products was investigated against heating and Lactobacillus acidophilus La 5 and Bifidobacterium lactis Bb 12 and its combination. Result: Cheese had the highest mean values concentration of AFM 1 (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 AFM 1. Whereas, pasteurization only degraded 15.45%. In yoghurt, two strains of probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium lactis) each gradually reduced the AFM 1 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 AFM 1 in milk contaminated with 50.0 ng/kg or 75 ng/kg AFM 1 .Conclusion: The most extensive reductions of the AFM 1 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 AFM 1 was detected after three days using the combined strains.

Immunoglobulin G (IgG), chemical composition contents of bovine milk during the first week of postpartum and the effect of heat treatments on bovine colostrum IgG contents were evaluated. Individual milk samples were collected from five cows at 0 to 0.5, 1, 2, 3, 4, 5, 6 and 7 days postpartum. The obtained results showed that the total solids, total protein, fat and ash contents decreased irregular with time after parturition, while the lactose content had an opposite trend. IgG concentrations were higher significantly during 0 to 0.5 and 1 st days than those of other days postpartum, where the mean±SD of IgG concentrations were 122.60±5.24 and 118.44±5.90 g/L during 0-0.5 and 1 st days postpartum, respectively. However, IgG concentrations dropped markedly with time progress of lactation at the end of the first week (7 th day); it was 55.16±17.30 g/L that had dropped ratio of 55.01% when compared with its concentrations at 0 to 0.5 day. The IgG concentrations of thermally treated colostrum were decreased to 28.24, 30.27 and 30.18% at 63°C/30 min as well as 57.33, 73.54 and 95.1% at 72°C/15 s during 1, 2 and 3 days postpartum, respectively. On the other hand, the most thermal influence on IgG was at 100°C/10 min, where the percentage losses were 95.72% at 1 st and 100% at 2 and 3 days postpartum. The total amino acids values of bovine milk immunoglobulins (IgS) were highest at 0 to 0.5 day and dropped markedly with time progress of lactation.

The aim of this work was manufacture of probiotic Ras cheese and study the chemical, microbiological, sensory characteristics and cholesterol level compared with control Ras cheese. The results showed that the moisture content significantly decreased in all Ras cheese samples. Fat and salt contents of Ras cheese were nonsignificantly increased, while the titrtable acidity and total nitrogen were significantly increased with progress of the ripening period. The higher level of total nitrogen was found in Ras cheese made with of Bif. Bifidum, then in cheese contained Bif. Lactis. Also, the ripening indices showed higher level (S.N./T.N. ratio, N.P.N./T.N. ratio) in probiotic Ras cheese with progress of the ripening period. T.V.F.A. content in probiotic Ras cheese containing Bif. Bifidum or Bif. Lactis had the highest significant effect as compared with control cheese. The results showed that the highest level of cholesterol concentration in control Ras cheese, while the lowest level in probiotic Ras cheese made by using Bif. Bifidum. The probiotic strains found viable during the ripening period and the increasing in total bacterial counts and the decreasing of Moulds and Yeasts counts. Lactic acid bacteria decreased with progress the ripening period in all samples. Ras cheese produced with Bif. Bifidum, The higher scores of sensory evaluation while the sample of Bif. lactis had the lowest scores as compared with the control cheese. Results obtained showed that the potential advantages of using the probiotic strains to produce safe and healthy cheese.