Efficacy of treatment of reusable grocery bags with antimicrobial silver to reduce enteric bacteria

Reusable grocery bags are seldom washed in homes and can become contaminated with enteric bacteria during use in grocery shopping. The goal of this study was to evaluate the efficacy of a cloth fiber grocery bag impregnated with silver in controlling enteric bacteria and viruses in three different settings. The reusable grocery bags were evaluated for bacterial survival in the laboratory, for bacterial growth in the trunk of a car, and for bacterial contamination when used by volunteers over 4 months. In the laboratory, the treatment was found to reduce Escherichia coli, Salmonella Choleraesuis, and Staphylococcus aureus counts by more than 99.9% within two hours and the MS2 virus and murine norovirus by 99.5%. When placed in a car trunk during warm weather, the silver treatment was capable of reducing bacterial counts in bags containing meat juices even under conditions that ordinarily promoted growth of bacteria. After being distributed to 38 households in Southern California for use over 4 months, the bags were found to have significantly fewer coliforms than non-treated canvas bags. The major significance of these findings is that the broad antimicrobial properties of silver make it a useful component of commercially available reusable grocery bags.