Enhancing Food Preservation with Single Atom Catalysts: A Novel Approach to Antimicrobial Packaging

Abstract

Introduction: Traditionally, antimicrobial agents in food packaging face the challenge of high cost, rapid exhaustion, and the inability to inactivate a broad spectrum of microorganisms. Single-atom catalysts (SACs) mimic natural enzymes to catalyze production of reactive oxygen species that inactivate a broad range of foodborne bacteria.

Purpose: To quantify the inactivation of select spoilage and pathogenic bacteria by ROS generated by Co-incorporated SACs in a packaging film.

Method: E. coli ATCC 25922, Listeria innocua ATCC11288, Leuconostoc lactis ATCC 15520, Listeria monocytogenes, Salmonella enterica ser. Typhimurium BAA190 were inoculated at 5 log CFU/ml into SACs suspension with concentration ranging from 0.1 g to 1 g/L (n=3). Additionally, circular disks of Co-SAC incorporated Polylactic acid (PLA) films (10 mm diameter) were incubated in 5 log CFU/ml E. coli ATCC 25922 suspensions. Samples were stored at 4℃ for 72h, with sampling intervals every 24 h. Bacteria were enumerated on appropriate selective media, and the surviving colonies were counted.

Result: Higher Co-SACs concentrations and longer incubation enhance efficacy against E. coli and S. enterica (P < 0.05), but not the other tested bacteria. Significant reductions of E. coli occurred 3.4± 0.34a log CFU/ml at 1g/L Co-SACs, compared to 2.84±0.06b at 0.5g/L 72 hours (P < 0.05). At 6h, 1 g/L Co-SACs reduced E. coli by 1.22 ± 0.07c log CFU/ml, significantly lower than at 72h.Similarly, S. enterica exhibited a 4.33±0.03c log CFU/ml reduction at 1g/L Co-SACs (P < 0.05). In contrast, Leu. lactis showed a minor reduction (0.45±0.06 log CFU/mL), while Listeria spp. remained unaffected at all SAC concentrations. Incorporation of Co-SACs (1 g/L) into the film resulted in a small increase in E. coli reduction (3.68±0.02 log CFU/ml) after 72 hours.

Significance: Co-SACs demonstrated strong antimicrobial potential towards some selected bacteria, highlighting their promise for enhancing food safety in packaging films.