At 20 mg/mL, the inhibition zones decreased, ranging from 3.0±0.5 mm (E. coli) to 4.0±0.5 mm (Bacillus cereus). The lowest concentration (10 mg/mL) showed very minimal antibacterial effects, with inhibition zones between 1.5±0.5 mm (Salmonella typhimurium and L. monocytogenes) and 2.0±0.5 mm (E. coli, S. aureus, and B. cereus). These findings indicate that Zn-PMA has good antibacterial activity, with L. monocytogenes being the most susceptible and E. coli showing the least inhibition at higher concentrations (Figure ).