The effect of the addition of inulin and manganese chloride (MnCl2) to milk before fermentation on the amount of antibacterial metabolites produced in fermented milk was studied. Normal and modified fermented milks were produced and the lactic acid and hydrogen peroxide (H2O2) contents were determined using standard analytical procedures. The well in agar diffusion method was used to determine the antibacterial effects of the cell free fermented milks on Staphylococcus aureus and E. coli.

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... s obtained showed that addition of the compounds increased the amount of lactic acid and H2O2 in the modified milk. Highest amounts of lactic acid (6197.50 mg/L) and H2O2 (42.83 mg/L) were obtained in the sample containing highest amounts of inulin (7 g/L) and MnCl2 (2 mg/L). The largest zones of growth inhibition for S. aureus and E. coli were obtained in samples containing 5 g/L inulin, 2 mg/L MnCl2 and 7 g/L inulin, 2 mg/L MnCl2, respectively. However, larger zone of growth inhibition were generally observed with E. coli. The inclusion of these substances significantly increased the amounts of the antibacterial metabolites and increased the inhibitory effect on S. aureus and E. coli. Therefore addition of such compounds to milk before fermentation should be encouraged to improve the probiotic and health potentials of fermented milk.