Antimicrobial Efficacy of Silver Nanoparticles (AgNPs) in Combination with Hand Sanitizer against Foodborne and Spoilage Bacteria
Neha Chatterjee *
School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India.
Akshada Shankar Ganesh
School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India.
Arjya Roy
School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India.
Aniesha Owlak
School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India.
*Author to whom correspondence should be addressed.
Abstract
Silver nanoparticles (AgNPs) are recognized for their broad-spectrum antimicrobial properties against foodborne bacteria, including E. coli, S. aureus, and B. subtilis. This study investigated whether AgNPs at varying concentrations (0.10%, 0.25%, 0.50%) could enhance the antimicrobial efficacy of a diluted hand sanitizer (1%) against these three strains. Bacterial growth was monitored by optical density (OD600) at 2, 4, and 24 hours post-inoculation. UV-Visible spectroscopy confirmed AgNP synthesis (SPR peak at 430 nm). The optimum AgNP concentration was organism-dependent: 0.25% AgNPs with 1% sanitizer produced greatest inhibition of E. coli and B. subtilis at 4 hours, while 0.50% AgNPs showed superior and sustained inhibition of S. aureus at 4 and 24 hours. These differences are attributed to cell wall architecture. AgNP-enhanced sanitizers show potential for food safety applications, though cytotoxicity concerns require resolution before human use.
Keywords: Silver nanoparticles, AgNPs, antimicrobial activity, hand sanitizer, optical density, E. coli, S. aureus, B. subtilis