Bring your Own Bags

How green can it be by bringing one’s own reusable bags?

Provided you can always remember to bring that same one along each and every time on your visit to the grocer; and according to a 2018 Danish study, found that:

  • reusable polypropylene bags should be used 37 times ,
  • paper bags should be used 43 times,
  • cotton tote bags should be used 7,100 times before they make any eco sense.

However, the majority of shoppers will end up forgetting to bring along these bags for re-use on their next shopping trip and end up buying more re-usable bags. Eventually they will all be stock piled in their basement or storeroom, used once and potentially never to see the light of day again, ending up with a conundrum of sorts, where the means do not justify the ends.

The overall impact on the environment by these substitutes, as measured by Life Cycle Analysis, is much worse than the plastic ones they are meant to replace.

In 2008, the UK Environment Agency (UKEA) published a study of resource expenditures for various bags: paper, plastic, canvas, and recycled-polypropylene tote bags. Surprisingly, the authors found that in typical patterns of use and disposal, consumers seeking to minimize pollution and carbon emissions should use plastic grocery bags and then reuse those bags at least once—as trash-can liners or for other secondary tasks.

Conventional plastic bags made from high-density polyethylene (HDPE, the plastic sacks found at grocery stores) had the smallest per-use environmental impact of all those tested. Cotton tote bags, by contrast, exhibited the highest and most severe global-warming potential by far since they require more resources to produce and distribute. Making a paper bag also requires more energy and water than making a plastic bag.

An August 2011 study “Assessment of the Potential for Cross Contamination of Food Products by Reusable Shopping Bags” indicates that harmful bacteria like E.Coli, salmonella, and fecal coliform thrive in reusable bags unless they are washed after each use. Failure to do so could allow such resuable bags to become breeding grounds for food poisoning, skin infections such as bacterial boils, allergic reactions, triggering of asthma attacks, ear infections and the like. This study randomly tested resuable grocery bags carried by shoppers in LA, San Francisco and Arizona.

According to Charles Gerba, a University of Arizona environmental microbiology professor and co author of the above study:

“Our findings suggest a serious threat to public health… consumers are alarmingly unaware of these risks and the critical need to sanitize their bags after every use…the bacteria levels found in reusable bags were significant enough to cause a wide range of serious health problems and even lead to death, a particular danger for young children, who are especially vulnerable to food borne illnesses..”