Prosopis laevigata Mucilage-Based Silver Nanoparticles: Green Synthesis and Dual Antimicrobial/Antibiofilm Potential Against Foodborne Pathogens

This study explored the eco-friendly synthesis of AgNPs using Prosopis laevigata seed mucilage and assessed their antimicrobial, antibiofilm, and biocompatibility effects against foodborne pathogens. The AgNPs were mostly spherical, with sizes ranging from 2.5 to 56 nm (average: 14.69 nm), as confirmed by XRD and DLS analysis. They showed consistent antimicrobial activity, with MICs at 0.5 mg/mL and MBCs at 1.0 mg/mL across all tested strains, and inhibited bacterial growth by over 75% at 0.5–5 mg/mL, similar to or better than gentamicin. The antibiofilm performance was notable, with inhibitions of 76–84% against E. coli (1–10 mg/mL), 96–98% against S. aureus (0.5–10 mg/mL), 76–82% against Salmonella Typhimurium (0.5–10 mg/mL), and 70–84% against P. aeruginosa (1–10 mg/mL), surpassing gentamicin against E. coli and P. aeruginosa. Cell viability remained 100% at 0.25 mg/mL, and no significant changes in immunological parameters were observed, suggesting good biocompatibility at therapeutic doses. This research shows, for the first time, that P. laevigata mucilage is an effective bioreducing agent for green synthesis of AgNPs with antimicrobial and antibiofilm activity against both Gram-negative and Gram-positive foodborne pathogens. Its superior ability to inhibit biofilms compared to traditional antibiotics, along with its safety profile at therapeutic levels, makes these nanoparticles promising for food safety applications, antimicrobial coatings, and topical treatments. Overall, the findings support the use of native plant resources in green nanotechnology to address global challenges of antimicrobial resistance.