A study published by the University of Pennsylvania and George Mason University found that a ban on plastic bags by the city of San Francisco has led to an increase in E. coli infections. In the three months since the ban, deaths from foodborne illness in that city spiked by 46%.
With plastic bags forbidden, consumers are using reusable bags. While that’s great for the environment, most people don’t know that the bags should be washed regularly. When they are not washed, they become contaminated with pathogenic bacteria. The study’s authors said, “using standard estimates of the statistical value of life, we show that the health costs associated with the San Francisco ban swamp any budgetary savings from reduced litter.”
In fact, the study found that relative to other counties, deaths in San Francisco increased by 50 to 100%, and emergency room visits by a comparable amount. The same bans on plastic bags in other California cities showed similar effects.
The ordinance contains details about the requirements for reusable bags. They must have a life greater than 125 uses, and be capable of carrying at least 22 pounds over a distance of at least 175 feet. They must also be durable enough so they can be washed and disinfected at least 100 times.
Another study published in 2011 in Food Protection Trends found that 51% of all reusable grocery bags contain coliform bacteria, which indicate the presence of feces. In addition, most people do not use separate bags for raw meat and for ready-to-eat foods, including fresh vegetables and fruit. The same study showed that 97% of consumers said they never wash their reusable grocery bags.
And according to Sustainable Living at the University of Connecticut, 40% of those bags harbor molds and yeast that can trigger allergic reactions and infections. Almost 2/3 of reusable bags were contaminated with some type of bacteria.
The lesson in all of this is if you use reusable grocery bags, wash them. Frequently. Some bags are machine washable; others are not. Wash them with warm water and soap and turn them inside out to air dry. Also, use a separate bag for carrying raw meats, poultry, and fish the next time you shop. And always use the bags for groceries only.