This was originally published on barfblog.

The Internet is there to provide data for what you already believe.” That’s what Doug emailed me in a conversation we were having about the endless coverage of the supposed maim and chaos that reusable shopping bags have on public health.. The reusable-shopping-bags-are-killing-us discourse took a turn into the mainstream when the NY Post and San Francisco Chronicle covered a publishing-by-press-release paper by Jonathan Klick and Joshua Wright.

They also put their paper on the Internet, on the Social Science Research Network, carrying the tag line of U of Penn Inst for Law & Econ Research Paper. But not in a peer reviewed journal that deals with food safety, microbiology or public health.

Klick and Wright claim that something stinky has been going on since San Francisco banned plastic shopping bags, and the replacements, reusable polypropylene and or canvas bags, are killing people.

From the paper,

We examine the pattern of emergency room admissions related to bacterial intestinal infections, especially those related to E. coli around the implementation of the San Francisco County ban in October 2007. We find that ER admissions increase by at least one fourth relative to other California counties. Subsequent bans in other California municipalities resulted in similar increases. An examination of deaths related to intestinal infections shows a comparable

Krick and White choose to report hospital room illnesses and deaths from pathogenic E. coli – and omit statistics on other pathogens – and it’s not clear why. In the Chronicle, San Francisco health officer Tomás Aragón calls the research sloppy. I’m with him.
Cited in the research note is a paper from Williams and colleagues (2011) who have published the only peer-reviewed study on the microbial safety of reusable bags. They sampled 58 bags taken from shoppers in Arizona and California, finding coliform in just over half.  And E. coli matters more than coliform (which is commonly found on plant material and is not a good indicator of pathogen presence on food). At least E. coli demonstrates that a pathogen might be there. The Williams study showed generic E. coli can float around in bags – they recovered it in 12% of what they sampled (n=58).

An unanswered question is, can E. coli or other bugs be (or is it likely) transferred to any ready-to-eat foods, or somehow to food contact surfaces in the home? Seems like that matters. Just because the bacteria might be there, doesn’t mean it can contaminate a ready-to-eat food. No one has presented data to support that. We’ve done some cross-contamination work in bags recently and although I’ll wait for the peer review, the data shows that transfer is pretty unlikely.

I don’t know what happened in Frisco (I hear the folks from there hate that) but my guess is it ain’t the bags. I also visited in San Francisco in 2007, which correlates (but doesn’t prove causation) with the onset of the start of the illnesses. Maybe it was something I left behind.

  • If you don’t believe there will be contamination from reusing bags that contained dripping raw meat packages, then you are a fool and worthy of your “piling it higher and deeper”  title.  It’s true they can’t teach common sense in school.

  • Russell La Claire

    Think we will hang on to our well worn, occasionally washed canvas bags just a wee bit longer. Any idea if Klick and Wright have intention of putting the paper through the peer review process? 
    Sense of humor is a useful tool. Keep it.

  • So throw them in the washer occasionally.  I do, especially during norovirus season.

  • husna

     Shopping carts are full of germs that get transferred into resusable bags upon shopping. A simple swab of a shopping cart followed by some microbial analysis will confirm the pathogens lurking in there. 

     Just providing customers with a handle cleaning sanitizing wipe at the entry of the facility will not solve the crisis. If public health is truly a concern, then supermarkets need to contract with a company that can come and sanitize the carts every morning.

  • CorkyJackson

    Death by bag?!!  Hilarious!!  Yet another big plastics industry campaign of lies, rehashing old cigarette PR industry tactics which told us cigarettes were safe.  If there was ANY validity to their paper, the Centers for Disease Control would come out and shut things down.   We need to start requiring scientific integrity and ethics by law so that big business will be forced to stop lying to us about everything.  Guess what, despite the PR machine, climate change is real, fracking is bad, San Onofre is broken beyond repair and will be dangerous to restart, reusable bags are perfectly safe (I’ve been using them for two decades without incident), and Jonathan Klick and Joshua Wright are morons .  

  • I’ve been using reusable bags for close to ten years, and I’ve not had a food safety issue. 

    Only an idiot would put a dripping bag of meat directly into a reusable bag. 

    Bottom line you use the same commonsense with your bags that you use with your kitchen utensils: you mind the cross contamination.

  • Ben Mark

    The grocery stores should not allow the clerks on the check out counter to handle them of have the bags set on the conveyor belt. I refused recently to put my groceries on a conveyor belt after a person had a reusable dirty and bad smelly bag on it for the clerk to fill it. They should carry the stuff in their carts to the car and do with what they want.  But you may be right on this one, the carts and hand baskets are so filthy, it doesn’t make a difference.

  • Dr. Tomas Aragon completely refuted the Klick paper. It’s worth pointing out that Williams et. al. did not find e. coli of any type in bags collected from San Francisco, they didn’t type the e. coli that they did find so it may have been, and probably was, harmless. So you have Klick using a very suspect methodology to find disease caused by organisms that Williams didn’t actually find in the first place.

  • Ben Mark

    search for contaminated shopping bags and contaminated shopping carts and you’ll find more information as you’ll like to read.

  • i already did—but it wouldn’t display!

  • Marie Lehnhardt

    Avoid the problem all together -get a CRESBI crate! They’re dishwasher safe and hold way more than any bags, reusable or plastic!

  • Palomar Parkman

    The issue of Health concerns with reusable bags may be minimal but only an idiot would dismiss this as a non-issue. Basic logic will tell you that the potential for the spread of bacteria in unwashed reusable bags is obvious. Also, bacteria is spread via contact with the bag while loading and or unloading. Yes, shopping carts are another concern. Some stores now offer wipes at the door for customers to use on the cart handles.
    I am all for banning single use plastic bags as I agree with the environmental concerns of plastic. But single use paper bags should be an option for stores and customers without the mandated excessive fees for them being legislated by some towns and cities. This is where government oversteps the boundaries. Why should I have to pay 25 cents for a 5 cent bag because someone thinks I should be carrying a reusable shopping bag like they do. Absolute BULL!
    Frisco is a town outside of Dallas TX. I suggest the author visits there so he knows the difference.