Reusable Grocery Bags Contaminated With E. Coli, Other Bacteria

EDITORS NOTE: Being green isn't just something that happens on the farm, my wife and I also champion the same green efforts of our more urban friends. We recycle all of our paper, cardboard, tin and alumninum cans, glass, and plastic bags. A few years ago, we also started using reusable grocery bags. The University of Arizona report below opened my eyes, and I thought I needed to share this with my food-focused friends. I'll be washing our reusable grocery bags this week.

Reusable grocery bags can be a breeding ground for dangerous food-borne bacteria and pose a serious risk to public health, according to a joint food-safety research report issued today by the University of Arizona and Loma Linda University in California.

The study Assessment of the Potential for Cross Contamination of Food Products by Reusable Shopping Bags (PDF) randomly tested reusable grocery bags carried by shoppers in Tucson, Los Angeles and San Francisco. The study also found consumers were almost completely unaware of the need to regularly wash their bags.

"Our findings suggest a serious threat to public health, especially from coliform bacteria including E. coli, which were detected in half of the bags sampled," said Charles Gerba, a UA professor of soil, water and environmental science and co-author of the study. "Furthermore, consumers are alarmingly unaware of these risks and the critical need to sanitize their bags on a weekly basis."

Bacteria levels found in reusable bags were significant enough to cause a wide range of serious health problems and even death. They are a particular danger for young children, who are especially vulnerable to food-borne illnesses, Gerba said.

The study also found that awareness of potential risks was very low. A full 97 percent of those interviewed never washed or bleached their reusable bags, said Gerba, adding that thorough washing kills nearly all bacteria that accumulate in reusable bags.

The report comes at a time when some members of the California Legislature, through Assembly Bill 1998, are seeking to promote increased consumer use of reusable bags by banning plastic bags from California stores.

"If this is the direction California wants to go, our policymakers should be prepared to address the ramifications for public health," said co-author Ryan Sinclair, a professor at Loma Linda University's School of Public Health.
The report noted that "a sudden or significant increase in use of reusable bags without a major public education campaign on how to reduce cross contamination would create the risk of significant adverse public health impact."

Geographic factors also play a role, said Sinclair, who noted that contamination rates appeared to be higher in Los Angeles than in the two other locations – a phenomenon likely due to that region's weather being more conducive to growth of bacteria in reusable bags.

"As scientists, our focus was not on the relative merits of paper, plastic or reusable grocery bags," Gerba said. "Our intent was purely to provide relevant data to better inform consumers and lawmakers about the public health dimensions that could arise from increased use of reusable bags. With this knowledge, people will be in a better position to protect their health and that of their children."

Adapted from a University of Arizona News Release

Photo source: flickr.com member Luca Penati