Vol. 8, Special Issue 3 (2023)

The objective of the current study was to synthesize, characterize, and evaluate the antibacterial activity of silver nanoparticles (AgNPs) using an environmentally friendly approach against Streptococcus. A total of 100 milk samples were collected from various sources, and the culture-based method revealed that 27 samples (27%) tested positive for Streptococcus. The average zone of inhibition for tamarind fruit extract against Streptococcus was found to be 3 mm for pure cultures and 2.04±0.16 mm for milk isolates. Similarly, the mean zone of inhibition for moringa leaf extract was 2 mm for pure cultures and 1.00±0.14 mm for milk isolates. For both pure cultures and milk isolates, the average zone of inhibition of AgNO3 solution against Streptococcus was 10 mm and 9.19±0.35 mm, respectively. The mean inhibition zone of AgNPs prepared with Moringa oleifera against Streptococcus was found to be 16 mm for pure cultures and 14.11±0.43 mm for milk isolates. On the other hand, AgNPs prepared with Tamarindus indica exhibited a mean inhibition zone of 14 mm for pure cultures and 12.19±0.46 mm for milk isolates against Streptococcus. The average inhibition zone of tetracycline against Streptococcus pure cultures and isolates was 6 mm and 4.04±0.38 mm, respectively. Ciprofloxacin displayed a mean inhibition zone of 12 mm for pure cultures and 10.30±0.40 mm for milk isolates, while Ampicillin's mean inhibition zone was 18 mm for pure cultures and 16.33±0.50 mm for milk isolates. Similarly, ceftriaxone exhibited a mean inhibition zone of 10 mm for pure cultures and 8.00±0.36 mm for milk isolates against Streptococcus.