New Study Reveals the Potential Danger of Using Reusable Grocery Bags

I remember when only one or two stores offered reusable bags for sale to promote their "eco-friendly" and green commitment to the public. It seems that every store you enter has reusable bags to purchase - of course, it also has the store logo on the bag, too. Our grocery store has taken it a step further by adding insulated reusable grocery bags to keep frozen and cold foods cool until you get home. One supermarket offers designer reusable bags for only one dollar more than the ordinary reusable bags they offer. I do believe that using reusable shopping bags is something that we all should do for the planet. However, as with anything that becomes popular there will be studies and research telling us the problems with it. The same is true for reusable shopping bags.

According to the conclusions of a recent study conducted by researchers from the University of Arizona and Loma Linda University, large numbers of bacteria were found in every reusable bag they tested and a potential significant risk of bacterial cross contamination exists when consumers use reusable bags for groceries. The purpose of the study was to ascertain the potential risks created from utilizing reusable bags to carry groceries. The project was divided into three phases: Phase 1 researched the occurrence of bacteria in reusable shopping bags, Phase 2 researched the potential for microbial cross-contamination in reusable shopping bags and Phase 3 evaluated washing and/or bleaching the reusable shopping bags. The study, published June 9, 2010, was funded by the American Chemistry Council (ACC). ACC represents some of the very companies responsible for making plastic bags and other convenience products. Before you allege an unfair bias, you should examine the results of the study.

Researchers randomly selected shoppers entering grocery stores in the San Francisco Bay area, greater Los Angeles and Tucson, Arizona to interview and obtain reusable grocery bags that had already been used. A total of 84 reusable bags were collected from the three areas (all but four bags were woven polypropylene) to use in the test. Researchers also purchased four unused reusable grocery bags from local markets and four new plastic disposable bags to test in addition to the used bags. Interviews of shoppers reveled that most bags were used several times per week with 30% of shoppers admitting they used the grocery bags for other purposes including carrying books, snacks, clothes, biking supplies or other shopping. Only one-quarter of the shoppers separated raw meat into separate bags from raw vegetables and a mere 3% of the shoppers interviewed said they had ever cleaned reusable grocery bags.

The new cloth reusable bags and new plastic bags did not have any bacteria present when tested. However, all but one of the reusable bags obtained from shoppers tested positive for HPC bacteria and Coliform bacteria was present in 51% of the bags that were tested which included Escherichia coli (E. Coli) in 12% of the cases. Researchers also tested the growth of bacteria in stored bags by introducing raw meat juice to the bags and storing them in the trunk of a vehicle. Within two hours, the number of bacteria multiplied 10-fold at a temperature of 47° C.

The good news from this report is that hand or machine washing the reusable grocery bags reduced the bacteria by more than 99.9%. The report recommends that printed instructions should be required on all reusable shopping bags alerting consumers that reusable bags should be washed between uses and raw foods should be separated from other foods. I think it would also be wise to include an alert that a separate bag should be dedicated to raw meats only and that bag should be washed after each use.

Bottom line - continue to use your eco-friendly, green reusable shopping bags but remember to wash them after every use. It would also be advisable not to use reusable grocery bags for anything but transporting your groceries.

Source:

"Assessment of the Potential for Cross Contamination of Food Products by Reusable Shopping Bags"by Charles P. Gerba, David Williams and Ryan G. Sinclair (June 9, 2010)