WIth the multitude of hands that pass over them, shopping carts are germ traps. And when kids gnaw on cart handles, customers have reason to be more than concerned.

At a supermarket in Chevy Chase, Md., recently, several customers said they were horrified to see their youngsters mouthing the handlebar.

"Especially when they used to sit in the back of the cart, they would always put their mouths down onto the handlebar, or they would put their fingers on the bar and then put their fingers in the mouth," said Deborah Kriznik, a shopper and mother.

University of Arizona researchers tested shopping carts and found that their handles have more saliva, bacteria and fecal matter than public toilets. Kids are sometimes the culprits.

"They don't necessarily have the best sanitary habits," said Dr. Chuck Gerba, an environmental microbiologist at the University of Arizona. "And you're putting your broccoli right where the kid's butt was."

Other times, the cart contaminates the kids. Riding in a shopping cart near raw meat is one of the top salmonella risk factors for children, right below exposure to reptiles, according to a study by the Centers for Disease Control and Prevention in Atlanta.

"Children start playing with the meat and the meat wrapper, they can become infected that way," said Dr. William Schaffner, chairman of the department of preventive medicine at Vanderbilt Medical School in Nashville, Tenn. "It's not the cart itself, but what you put in it that matters."

To combat germs, 20 supermarkets across the country have taken an innovative step, installing sanitizing devices for shopping carts. The machines look like mini car washes for carts and spray a misty peroxide solution over the entire cart after every use that is guaranteed to kill 99 percent of germs, including E. coli and salmonella.

Many grocery stores across the country, like the Chevy Chase Supermarket in Chevy Chase, Md., used to offer wipes for customers who complained about germs on their carts. But some customers worried about the chemicals in the wipes themselves, which were hazardous to children.

To calm customers' worries, some store decided to invest nearly $8,000 a year on PureCart Systems, which disinfects shopping carts.

"I want people when they walk into my store, to know it's a clean, neat, well-organized store, and when you look at the baskets, you don't have to think twice about it," said Kevin Kirsch, co-owner of Chevy Chase Supermarket.

While it may sound over-the-top, customers seem to love it, especially those with young children. Kirsch runs the tiny, kid shopping carts, shaped like fire engines and police cars, through the device all the time.

Shopper Kriznik said, "It's really innovative. It's one-of-a-kind. I've never seen anything like this in the area."

Another shopper, Christy Phillips, said, "I am a paranoid parent. But I do think that it's a fantastic idea because then you know and you're not worried about it."

The cart wash not only gives parents some piece of mind, but offers them some assurance that the only thing they'll pick up at the supermarket is their groceries.