Cross-contamination happens when raw meats and produce touch pre-cooked foods and other items as they’re placed side by side in already soiled bags. Clean your reusable bag every time you shop to further prevent cross-contamination. When shopping, protect items, and your bags, by double bagging groceries, especially the potentially leaky items, with plastic produce or meat bags. As an extra step at home, designate and label bags you’ll use on a continuous basis only for meat, produce, dairy, dry goods, and cleaning supplies.

General Good Cleaning Practices

Shopping bags used for meats, produce, and precooked foods should be washed after every use when carrying food, just as you would launder a kitchen towel. Here are a few more general cleaning pointers:

Do remove the bottom insert of your reusable bag before washing.Do clean inserts—which are usually cardboard or cardboard covered with vinyl or fabric—with a disinfecting spray cleaner.Do turn each bag inside out before washing for better cleaning.Do pay special attention to the nooks and crannies around the seams when hand-washing a bag.

Cleaning Canvas and Fabric Reusable Bags

You may find instruction labels on how to protect your natural canvas shopping bags. If your canvas bag doesn’t have instructions, use the following cleaning methods:

Wash it in hot water with your usual detergent. Hot water is necessary to kill E. coli and other bacteria on fabric. Allow a canvas bag to air dry after reshaping it Hand-wash in hot water and air dry a mesh, hand-knit, or crocheted grocery bag made of any material, including jute. Don’t bring a canvas or cloth bag to the store until it is completely dry; a moist environment encourages the growth of mold and mildew. Don’t put a canvas (or cotton) bag in the dryer if you don’t want it to shrink.

Cleaning Plastic (Polypropylene) Reusable Bags

For woven bags that are made of composite man-made fibers like polypropylene and recycled PET (a type of plastic resin), hand-wash or use the gentle cycle on your washer using warm water. Here are a few dos and don’ts:

Disinfect the bag with Lysol or an antibacterial wipe if you don’t have the time to put your bag into the wash. Air-dry polypropylene bags. If using chlorine bleach, be certain it is heavily diluted as pure bleach could weaken the fibers. Don’t put polypropylene bags in the dryer because they could melt.

Cleaning Nylon Reusable Bags

Clean a reusable nylon bag (without insulation) either in the wash or by hand in warm water. Note the do’s and don’ts:

Use warm water and the gentle cycle (or hand wash) in the washing machine.Use warm and soapy water when washing by hand.Pay attention to cleaning the nooks, crannies, and crevices of the bag while washing by hand.Air-dry nylon bags.Don’t put nylon bags in the dryer because high heat may cause the material to melt, become distorted, or weaken.

Cleaning Insulated Reusable Bags

Insulated shopping bags or totes must be cleaned as frequently as any other reusable grocery bag. Since they’re made from heavy-duty nylon with waterproof cooler bag liners—typically made of thin silver foil liners, PEVA (polyethylene vinyl acetate), or extra-durable heat-sealed PEVA—you’ll need to spray and wipe them with disinfectant solutions. If your bag or tote has zippers, make sure to wipe down or spray those, too.