Any eco-shopper’s adventure to the grocery store or farmers market probably isn’t complete without a few handy dandy reusable bags in tow. Good for you, you green-minded shoppers! But did you know that if you don’t wash those reusable bags consistently, you could also be toting around E. coli and other bacteria?

Think about it. Your raw meats and unwashed fruits and veggies are all milling about with each other and rubbing their potential germs all over your beloved bags. Plus, if you're using those bags to carry around books, thrift store finds and any other bits and pieces you may need to lug around, you're adding more germs to the mix. And if you’re not washing those reusable bags, that bacteria is just along for the ride.

In fact, researchers found coliform bacteria in half of 84 reusable bags tested in Arizona and California in a 2010 study conducted by the American Chemistry Council. The study also found the dreaded E. coli in 12 percent of the bags and some form of bacteria in all but one of the bags. Eeesh.

Even worse, these bacteria can live on the bags for hours, or even days. But you don't have to revert back to the dreaded plastic bag (please don't!). Follow these four easy tips to keep your reusable bags squeaky clean (naturally, of course).

1. Toss them in the laundry. Easy schmeasy. Just add your cloth reusable bags to your regular laundry and that’ll get rid of all that bad bacteria.

2. Wipe ‘em clean. If you own reusable bags made from a plastic material, spray them with a solution of vinegar and water, let the mixture soak in and then wipe them clean. The vinegar will kill any bacteria that might be hanging around.

3. Air dry. After you get home from the store, let your bags air out (unless they're headed straight for the washing machine). Don’t just stuff them in a closet. Moisture and warm air will just encourage bacteria to grow. Instead, hang them in a well-ventilated area to dry.

4. Keep items separate. Use specific bags for meats and others for produce. Keeping your foods separate will prevent cross contamination. If you’re buying meat, you should always wash the bag after each use.

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image: Xavier Encinas