Antimicrobial Efficacy and Life Cycle Impact of Silver-Containing Food Containers

Food loss and waste due to spoilage represents a critical global challenge to sustainable food consumption and production in a resource constrained world. Silver (Ag) has been used in food storage applications to reduce the food spoilage rate through its antimicrobial properties. However, the efficacy and safety of commercial silver-treated food storage containers are not well characterized regarding the potential life cycle implications of their design and application. This study aims to determine the antimicrobial efficacy and quantify silver leaching from a commercial container product containing micronized silver particles over simulated washing and end-of-life landfill disposal. The leached silver results were then used for examining the environmental impacts of the product at 10 impact categories. With a loading of 8.8 ± 0.6 Ag μg/g in polymer matrix, the silver-containers were ineffective in inhibiting the growth of common foodborne pathogens. After four washing cycles, the containers only released <0.25% of the total silver content in the presence or absence of dishwasher detergent. Regardless of detergent usage, dissolved silver was the predominant form of released silver due to oxidative dissolution of migrated silver nanoparticles (nAg). The application of toxicity characterization leaching procedure (TCLP) on the washed containers resulted an insignificant silver leaching below the 5 mg/L federal standard for landfill waste disposal. Life cycle assessment (LCA) indicates a slight increase (1-1.4%) of the overall environmental impact of silver-enabled food storage container compared to the nonsilver counterpart. Overall, we argue that it may not be worth the additional environmental cost to incorporate micronized silver in the containers studied. More effort is needed to improve the efficacy to extend the shelf life of foodstuffs through better product design and nanomaterial application.