I read a blog every day called Barf Blog. Barf Blog is a project of University of Kansas associate professor of Food Safety Doug Powell. Powell has an extensive background in microbiology as well as a biting, entertaining wit. Barf Blog may be an academic exercise, but it sure doesn't read like one. Several times a day, Powell and a bunch of his food safety pals publish posts about how food safety and microbiology effect every day life. They do this with a tremendous sense of humor and a complete disavowal of scare tactics. Barf Blog is living proof that reason and rational thought will save the day every time.
OK with that said, last week, Ben Chapman wrote a great post debunking the results of a bogus study commissioned by the Canadian Plastic Industry Association that purported to prove that reusable grocery bags are a health hazard. They proved no such thing, but the story made it into the pages of my local paper anyhow.
Swab-testing of a scientifically-meaningful sample of both single-use and reusable grocery bags found unacceptably high levels of bacterial, yeast, mold and coliform counts in the reusable bags. The swab testing was conducted March 7-April 10th by two independent laboratories. The study found that 64% of the reusable bags were contaminated with some level of bacteria and close to 30% had elevated bacterial counts higher than the 500 CFU/mL considered safe for drinking water.
Coliform bacteria, yeast and mold are everywhere and trying to eliminate them is the ultimate fool's errand. Their presence on the surface of a grocery bag, an apple or your hands means nothing. Coliform bacteria in your drinking water is an all together different situation, but a grocery bag isn't a glass of tap water. There is coliform bacteria anywhere where there are life forms that poop nearby. Finding generic coliform bacteria in water is a test to see if a water source has been exposed to poop or not. Poop, human and otherwise, can carry all manner of dangerous pathogens and coliform counts in water samples are an an important and easily detectable warning sign. On its own, most coliform bateria is harmless. However, a very specific form of it is bad news and that form has a name, E. coli 0157:H7. The study found zero traces of 0157:H7 and states that finding clearly:
No E. coli or Salmonella was detected in any of the bags.
However, it follows up immediately with the conjecture that they might find some if they look harder. Spare me. That finding is buried in the Specific Results section of this paper:
The unacceptable presence of coliforms, that is, intestinal bacteria, in some of the bags tested, suggests that forms of E. coli associated with severe disease could be present in small but a significant portion of the bags if sufficient numbers were tested.
The finding of 500 CFU/mL makes me wonder too, because that's a measure for liquids. It means Colony Forming Unit per milliliter. The authors of this "study" found 500 colony forming units of coliform bacteria in a milliliter of grocery bag. Huh?
Clearly, this study was the handiwork of an industry feeling the pinch of people switching to reusable grocery bags and that's it. Releasing unscientific findings in the form of press release preys on most peoples' scientific illiteracy and fears. It's ridiculous, but what's really ridiculous is the outright fear mongering and the illogical leap to the idea that reusable grocery bags are responsible for food-born illness.
But I suppose it's no more illogical and ridiculous than the claim that I need to use reusable grocery bags so that I can save the earth, what ever that means.
So why not this? The simple and rational reason to switch to reusable grocery bags is that they are a more efficient use of resources and they cost less money over time. You're not going to get impetigo from them any more than you're going to save the rain forest. What you will do though is reduce the amount of solid waste you generate, help to reduce the US's dependence on imported oil and you'll help to cut down on the amount of garbage that ends up being washed into waterways.
Their use is a smart way to lead a more efficient life, so go be more efficient and ignore industry-sponsored findings.