Although durable shopping bags may seem environmentally friendly, a survey carried out by ABC 7 News, a US-based news station in the Washington DC area, found that these bags could pose a risk to your health by becoming a home for bacteria, fungus and mould.

To carry out a quick survey of the dangers that might lurk within durable bags, ABC 7 collected 10 bags from shoppers across its broadcasting area, had them swabbed, then sent to a laboratory to find out what was living inside them. The lab found half of the bags contaminated to the point where they should be thrown away for safety reasons.

Every bag showed a presence of bacteria, fungus, mould, or yeast. Several bags had a combination of some or all of those.

"Think of these organisms all being in that bag," they said. "You put your milk in that bag, it's wet on the outside, the organisms find a place to grow -- all they need is moisture."

No contamination or dangers to health were found in two brand-new bags which were tested in the same study, so the contamination clearly came after the bags had been used.

One user's bag in the ABC 7 test came back with four times the bacteria that would be considered safe for drinking water. It also had four kinds of fungus, and what could be shigella, a fecal pathogen similar to salmonella.

”This result confirms our own reservations about durable bags,” says Michael Laurier, CEO of Symphony Environmental Ltd., the specialists in oxo-biodegradable plastic.  "We have noted the results of studies carried out by Guelph Chemical Laboratories in Canada, and the University of Arizona which reached almost exactly the same conclusions.  The best solution for public health is a plastic carrier bag.

"The only problem with plastic carrier bags is that they can lie or float around in the environment for decades, but not if they are made with d2w technology. d2w converts ordinary plastic at little or no cost into a material with a completely different molecular structure, which can be bio-assimilated in the environment by a similar process as a leaf.”