Reusable Shopping Bags: Green But Unclean

Over the past few decades fewer supermarkets have begun offering traditional brown paper shopping bags, and most have turned to lightweight, strong plastic bags. This convenience comes at a price when the bags end up in landfills, strewn along highways, or in the ocean where they can choke and kill marine life.

In the age of "reduce, reuse, and recycle," re-using sturdy shopping bags makes good sense and is a logical solution. If you're going shopping anyway, just bring along your own bag. You'll save the environment (and, in many stores, save a nickel).

But there one important factor than many eco-conscious consumers overlook: cleanliness. One undeniable benefit of a new bag (whether paper or plastic) is that it is, well, a new bag. It has not been used before, and therefore is free of contaminants. You don't need to think about what potentially toxic substances the bag may have previously been used to transport.

Most folks don't give the hygiene of their reusable bags any thought, but according to a new study from researchers at the University of Arizona and Loma Linda University, they should.

The study, "Assessment of the Potential for Cross Contamination of Food Products by Reusable Shopping Bags," found that nearly all (97%) of shoppers who use reusable bags do not regularly (if ever) clean them. Furthermore, most of us freely mix meats, vegetables, and other foods in the same bag, and don't think twice about it.

According to the study, "Reusable bags, if not properly washed between uses, create the potential for cross-contamination of foods. This potential exists when raw meat products and foods traditionally eaten uncooked (fruits and vegetables) are carried in the same bags, either together or between uses. This risk can be increased by the growth of bacteria in the bags."

Indeed, half of the bags that researchers examined tested positive for coliform bacteria, and 12 percent had E. coli bacteria. These bacteria, and others, contribute to the 76 million cases of food poisoning each year.

So what's an eco-friendly shopper to do?

Fortunately the answer is simple, and the same one that has saved countless lives over the centuries: wash your hands, wash your food, and wash your bags. The researchers found that over 99% of the bacteria were eliminated after either hand washing or a bout washing machine. Be green, but be clean.