Study: Wash reusable grocery bags to avoid bacteria

 

By Kaye Spector

Plain Dealer Health and Medical Writer

 

Those reusable fabric shopping bags may be kind to the environment, but they may not be good for your family's health – if you don't wash them.

A new study, in which researchers randomly tested 84 reusable grocery bags carried by shoppers in Tucson, Los Angeles and San Francisco, found that more than half of the bags were contaminated with food-borne bacteria.

Twelve percent was E. coli, a bacterium that can cause food poisoning. While abdominal cramps and diarrhea are most common, serious – sometimes life-threatening – complications can develop, especially among young people and older adults.

Ninety-seven percent of the shoppers in the study said they do not wash their bags, nearly all of which were made of woven polypropylene.

“If you're going to use these bags, you need to take care of them,” the study's co-author, Charles Gerba, said Thursday. “The last thing you want to do is grow salmonella in your sack.”

The main concern, said Gerba, a microbiologist and professor at the University of Arizona, is cross contamination: a package of meat leaks juice in a bag. The bag is unpacked, then placed back in the hot car trunk until next week's shopping trip, when the bag is filled with vegetables.

By then a horde of bacteria may line the inside of the bag and transfer to the vegetables or your hands and spread elsewhere.

“It's a gamble,” Gerba said.

While unwashed bags might not result in headline-grabbing outbreaks, Gerba said, “Our data says it may be a common risk that might be overlooked.”

Despite the study’s findings, the Cuyahoga County Health Department has not traced any food-borne illness to reusable bags, said environmental health services director John McLeod.

But as more and more shoppers are adopting reusable bags — either for environmental concerns or to stem the tide of household plastic bags — washing the totes is a good habit to adopt, said Matt Carroll, Cleveland Public Health Department director.

“If you can keep E. coli out of your house by washing the bags, then obviously you should wash the bags,” Carroll said.

A thorough washing will kill nearly all bacteria that can accumulate in the bags, said Gerba.

“There’s a lot of different factors that go into bacteria growth: moisture, heat and having the bacteria itself,” McLeod said. “We want to make sure we break that cycle.”

Jeff Heinen, of Heinen’s Fine Foods, says that although they remain a minority, more and more of his customers are taking home groceries in reusable bags.

The local chain has been selling the bags for 10 years. At first they were made of cloth; now they are made of the woven polypropylene. The bags can be hand- or machine-washed in cold or warm water on gentle cycle and hung to drip dry. Do not put the bags in the dryer.

“It’s no different than your refrigerator,” Heinen says. “You want to clean it occasionally.”