The Canadian Plastic Industry Association commissioned a study concluding that using cloth bags is bad for your health because they're full of bacteria (and certainly not because using cloth bags is bad for the profitiblity of Canadian Plastic Industry Association members!). They hired an ex-health regulator (Dr. Richard Summerbell, Director of Research at Toronto-based Sporometrics and former Chief of Medical Mycology for the Ontario Ministry of Health) to say that cloth bags put you at risk of "skin infections such as bacterial boils, allergic reactions, triggering of asthma attacks, and ear infections". Of course, it's bullshit, and the regulator who traded his credibility for a consulting fee should be ashamed of himself.
Um, yeah except that coliform isn't an indicator of really anything in a shopping bag. It's a great indicator of water quality, but not great for food (coliforms are all over the place, including on produce). And mean relatively nothing.
The lack of real data is probably why it was reported in CFU/ml (a water measurement — pretty hard to tell what a ml of a shopping bag represents). The most telling data was that no generic E. coli or Salmonella was found.
Are reusable bags really a food safety concern?
(via Consumerist)