(FOX19) - Using the same bag for groceries is a great way to shop green.
However, mixing meats and produce in the same reusable bags without washing them after each use can become more harmful than you think.
Hundreds of reusable grocery bags were tested and the results are eye opening.
"We're talking maybe millions of bacteria in some of the bags, it depends how people handle them and store them," said Dr. Charles Gerba, a microbiologist with the University of Arizona. He spear-headed the study.
While using the same bag every trip to the store is great for the environment, there is a high probability for cross contamination.
"Meat products leaking in your grocery bags, putting E-coli or salmonella in the bag and then you use that same bag when you go shopping the next time for raw produce or you come in contact with organisms that can make you ill," said Gerba.
So the key is to wash the bags. Dr. Gerba suggests washing them after every use.
"Less than three percent of people admitted to ever having washed their reusable grocery bags," said Gerba. "Also may people use them for storing other objects like their laundry, gym clothes, or other types of products in them which can result in cross contamination. I can't believe that some people will bring your underwear to the laundromat in the same bag they'll actually put their raw vegetables or tomatoes in."
It doesn't mean you should throw the bags away. Just wash them, store them inside your home and not the trunk of the car. That dark place acts like an incubator for bacteria that you certainly don't want sharing a ride home with your food.
Also, be sure to separate the meats from the raw produce and throw the bags in the wash before the next trip to the store.