Reusable grocery shopping bags are great for the environment and reduce paper and plastic waste going into our landfills. Some stores even offer a discounted price for groceries if you bring your own shopping bag. Reusable bags may be made from fabrics ranging from natural fibers like cotton and jute to woven synthetics, knitted or crocheted in an open weave or made from plastic film more sturdy than the common plastic bag.
But are they really safe to use over and over for the food your family eats?
A joint food-safety research report by researchers from the University of Arizona and Loma Linda University in California found that most reusable grocery shopping bags harbor multiple harmful bacteria. More than fifty percent were contaminated with bacteria, and E.coli was found in over twelve percent of the tested bags. During their study, in a quick survey at a grocery store, ninety-seven percent of shoppers admit that they have never washed their reusable grocery shopping bags.
Cross-contamination happens when meats, produce, and pre-cooked foods are placed in soiled bags. And if you use the bags on occasion as a diaper bag or gym bag, even more bacteria enter the food chain.
- Shopping bags should be washed after every use when carrying food just as you would launder a kitchen towel. This is especially critical for bags used for meats, produce, and precooked foods. Bags used for cleaning supplies or dry goods can go a bit longer between washings.
- Have more than one bag and label each bag as Meat, Produce, Dairy, Dry Goods, Cleaning Supplies, etc. Or use a different-colored bag for each type of purchased item. This will prevent cross-contamination. Always double bag with a plastic bag any items like poultry and meats that may leak. Even if the contents don't leak, there could be bacteria on the packaging material.
- Consider purchasing reusable hemp bags because hemp has naturally anti-mold and antimicrobial properties.
- Use grocery reusable bags only for carrying food—no gym clothes, diapers, chemicals, or gardening supplies. A soccer team in Oregon was infected with the norovirus after a reusable grocery shopping bag was used for gear.
- Do not leave unwashed bags in your car. The high heat is a perfect incubator for bacteria to multiply.
- Do not place clean reusable shopping bags in the baby carrier section of the grocery cart. This is the most contaminated area of the cart and bacteria can transfer to your shopping bags.
- Insulated shopping bags must be cleaned as frequently as those that are not insulated.
How to Wash Reusable Grocery Bags
Some bags have labels with instructions on how to launder and you should follow those directions. If your bag doesn't have instructions and is a woven canvas bag, wash it in hot water with your usual detergent. The hot water is necessary to kill E. coli and other bacteria. These can be line dried or put into the dryer. Nylon bags should be laundered the same way but should be air-dried. High heat can cause the nylon to melt or become distorted and weaken.
For bags that are made of composite man-made fibers like nonwoven polypropylene and recycled PET, hand wash or use the gentle cycle on your washer. However, this is the one time that hot water should always be used when washing by hand or on the gentle cycle. These bags should never be put in the dryer on high heat. Allow them to air dry.
Skip the chlorine bleach which may damage and weaken the bag fibers. If you wish to take the extra step of disinfecting the bag, use pine oil or a phenolic disinfectant like Lysol.
For all types of grocery shopping bags, remove any inserts (many are cardboard), turn each bag inside out before washing, and pay special attention to the nooks and crannies around the seams. Clean any inserts with a disinfecting spray cleaner.
Mesh bags, whether manufactured, hand-knit, or crocheted from natural fibers, synthetics, or plastic should be hand washed in hot water and allowed to air dry.