Paper or Plastic (or Deadly Food-Borne Pathogens)?

The Reusable Grocery Bag Plague

Paper or Plastic (or Deadly Food-Borne Pathogens)?
A shopper packs groceries into reusable bags in Brooklyn, N.Y.
Photograph by Chris Hondros/Getty Images

A couple of years ago, our grocery store gave us a reusable nylon shopping bag, and I try to use it. Usually, however, I don’t. I rarely have the bag with me when I go to the store, either because I’m coming from work, because my wife is carrying it around with her gym clothes in it, or simply because I forget. I feel bad about this—because of my absent-mindedness, a landfill is that much fuller. I picture the plastic bag I use to bring my cereal and eggs and chard home as it gets blown out to sea, where a seagull or dolphin chokes on it.

From now on, though, I’m going to feel less guilty after coming across this working paper that suggests reusable shopping bags can kill you. Recent years have seen a raft of bans put in place on plastic bags—Los Angeles and San Francisco both have them, as does China. In their paper, University of Pennsylvania economist Jonathan Klick and the lawyer Joshua Wright decided to look at emergency room admissions for illnesses related to food-borne bacteria before and after San Francisco County imposed its ban in 2007. They found that the problem had increased by more than one fourth, and that deaths had risen by the same amount.

The issue, it seems, is that the vast majority of shoppers who re-use bags never clean them. This is not a surprise; I don’t either, any more than I clean the bag I take to work every day. Most people also don’t pay close attention to whether they’re using a bag to carry mesclun greens and apples that they used a week earlier to tote chicken breasts or other raw meat—or for that matter, a dog leash and their soccer cleats

It turns out this isn’t the first time researchers have shown the risks associated with reusable bag use. In 2010, biologists at the University of Arizona and Loma Linda University did a study in which they interviewed shoppers and then tested their reusable bags for bacteria. Ninety-seven percent of the shoppers said they didn’t wash their bags regularly. Only 25 percent said they used separate bags for meat and vegetables. When the biologists tested the bags, they found coliform bacteria—mostly harmless in themselves, but an indicator of pathogens—in 51 percent of the bags. They found E. coli—which is very far from harmless—in 12 percent of the bags.

The good news is that washing the bags, either by hand or in a washing machine, reduced the bacteria by more than 99.9 percent. The authors of the 2010 study recommended that bags carry printed warnings on them to that effect.

As for me, I’m pretty good about getting a separate bag for meat—I am acutely aware of the possibility of meat juice spillage. From now on, I will try to wash my reusable grocery bag. But it’s hard enough to remember to simply take the thing to the supermarket, much less remember whether I’ve washed it since I last used it—and what it was I last used it for. What’s more likely to happen, I imagine, is that I’m going to “forget” my bag more often. I’ll bet that hearing these results will have a similar effect on many people.

For a certain sort of ecologically conscious soul, though, it’s possible that this news will have the opposite effect. The inconvenience of reusable grocery bags is what give them their power as symbols of green virtue, along with reusable water bottles and hybrid cars. But if reusable bags become not just inconvenient but actually dangerous, they become that much more weighty as a sign of the sacrifices one is willing to make for the planet. A reusable bag with a dire warning about fatal fecal-borne bacteria on it says, in effect: “I am risking my life (and that of my family) to save a seabird from choking to death on plastic. What have you done for the environment lately?”

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