Professor Charles Gerba, the lead researcher, swabbed the handles of 85 carts in four states for bacterial contamination.
Gerba says 72% of the carts had a positive marker for fecal bacteria. When they examined some of the samples, they found Escherichia coli, also known as E. coli, on half of them.
Researchers say they actually found more fecal bacteria on grocery cart handles than you would typically find in a bathroom, mainly because bathrooms are disinfected more often than shopping carts.
Since most stores do not routinely wash and disinfect their carts, it's up to you to do it.
Scientists say this study helps explain why earlier investigations found kids who touch the handles, are more likely than others, to get infected with bacteria like salmonella.
Gerba also says you should pay attention to what you put in reusable shopping bags. Make sure your meats and veggies are wrapped because bags that are not washed on a regular basis can become a what he called a "bacterial swamp."