http://www.thedenverchannel.com/news/25181234/detail.html This is a poorly written article, but I think it still conveys a useful point. Those reusable grocery bags that are being brought into stores are simply breeding grounds for bacteria. I think that the following statement from the comments section of that article says it best: At the very least, I think it would be a good idea to throw your cloth bags through the laundry after every trip. Of course, then you start running into problems with water usage. It's funny how 'green' ideas often have markedly bad-for-the-environment consequences. Maybe a biodegradable bag that's one-use-only is the solution.