Are reusable bags really a food safety concern?

The Canadian Plastic Industry Association (likely feeling reduced sales due to the popularity of reusable cloth bags) says that reusable bags are a public health risk. In a press release yesterday the plastic dudes touted the results of a bag swabbing study conducted earlier this year. Cited as the first study of its kind in North America, the plastics industry swabbed a whopping 25 bags, with 4 controls looking for anything they could find.

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.

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.

Not the best methodology design. Or reporting of results.

Not to be phased by the lack of data, Dr. Richard Summerbell, Director of Research at Toronto-based Sporometrics and former Chief of Medical Mycology for the Ontario Ministry of Health (1991-2000), who evaluated the study results said, "The main risk is food poisoning. But other significant risks include skin infections such as bacterial boils, allergic reactions, triggering of asthma attacks, and ear infections."

Wow. Maybe if you’re talking about yeast and molds? But when it comes to pathogenic microorganisms the data just isn’t there.

We use reusable bags all the time for our shopping and take a few precautions to maybe reduce any potential risks: we keep them dry; wash them every couple of weeks and use one-use bags for raw meat.

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About Ben Chapman

Dr. Ben Chapman is a professor and food safety extension specialist at North Carolina State University. As a teenager, a Saturday afternoon viewing of the classic cable movie, Outbreak, sparked his interest in pathogens and public health. With the goal of less foodborne illness, his group designs, implements, and evaluates food safety strategies, messages, and media from farm-to-fork. Through reality-based research, Chapman investigates behaviors and creates interventions aimed at amateur and professional food handlers, managers, and organizational decision-makers; the gate keepers of safe food. Ben co-hosts a biweekly podcast called Food Safety Talk and tries to further engage folks online through Instagram, Twitter, Facebook, YouTube and, maybe not surprisingly, Pinterest. Follow on Twitter @benjaminchapman.