Unwashed reusable grocery bags breed bacteria

Published: November 2, 2010

CLEMSON — Cloth shopping bags may be good for the environment, but are they good for your health?

“Reusable grocery bags are safe, but you do need to keep them clean,” said Pam Schmutz, Clemson University Home and Garden Information Center food safety specialist. “Hand or machine wash them in hot, soapy water at least once a week, and always wash after a spill. After washing, machine dry or turn inside out and hang dry. That will reduce the number of bacteria inside and outside the bag by more than 99.9 percent.” 

Research shows that the bags need to be cleaned regularly to keep them from becoming breeding grounds for germs. Researchers at the University of Arizona and Loma Linda University in California tested reusable bags from 84 people entering grocery stores. While the researchers did not find harmful bacteria, such as Salmonella or Listeria, they did find large numbers of bacteria commonly on surfaces and in the environment. Only two of 84 people — 3 percent of those who had their bags tested — reported cleaning their reusable bags.

“The greatest danger is from meat, fish or poultry juices contaminating the bag, or other foods with harmful bacteria that can make you sick,” said Schmutz (pronounced Schmootz), adding that packages of raw foods can have bacteria even on the outside. “Always remember to put packages of meat, fish or poultry in a disposable bag to catch leaks. The disposable bag can then be put in your reusable bag.”

And don’t mix uses for your reusable grocery bags. Researchers noted that 25 of the 84 people reported that they used their bags to carry nonfood items, such as books and clothes. 

“Only use your reusable grocery bag to hold food,” said Schmutz. “If you need to carry books or gym clothes or other non-food items, use a different bag.”

Food safety specialists also recommend that you:

• Put unpackaged produce in disposable bags. Not only can bacteria from the produce contaminate other foods, but the produce can pick up bacteria from the bag itself. If the produce is not cooked, the bacteria will survive.
• Never store unwashed reusable bags in a hot car where bacteria can thrive. This is a real concern in hot, humid climates like South Carolina.

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