Inhibition of Growth of Spoilage Microorganisms by Streptococcus thermophilus and Lactobacillus acidophilus in Cow, Buffalo and Goat Milk

Comparison of the inhibitory activity of pure and mixed cultures of Streptococcus thermophilus and Lactobacillus acidophilus against spoilage microorganisms, i.e., Escherichia coli, Pseudomonas fragi, Micrococcus flavus and Staphylococcus aureus, was done using cow, buffalo and goat milk. No antibacterial activity of S. thermophilus culture filtrate was observed against any of the spoilage microorganisms tested, irrespective of the type of milk and period of incubation. However, filtrates from L. acidophilus and mixed cultures of S. thermophilus and L. acidophilus exhibited significant inhibition of all test microorganisms. The inhibitory activity of lactic cultures was more evident in buffalo milk than cow or goat milk.