A supermarket cart can be exposed to the drippings from chicken and meat.

An Inside Edition investigation found disturbing evidence that supermarket shopping carts can expose shoppers – including small children who often ride in the carts - to harmful bacteria.

In a typical day, a supermarket cart can be exposed to the drippings from chicken and meat, and even young children still in diapers

Dr. Kelly Reynolds, a microbiologist with the University of Arizona, tells Inside Edition all are sources of contamination.

"You need to be aware that there could be harmful bacteria from raw meats and produce, and harmful viruses from people's hands that have been sick, present on shopping cart handles."

Inside Edition tested 30 carts at nine supermarkets to find what germs were lurking.

The syndicated newsmagazine tested carts with young children in them, swabbing and focusing on the areas most likely touched, like the handles and areas around the seats. The swabs were sent to an independent lab and tested for bacteria and fungus that can cause disease.

Inside Edition’s lab found several types of bacteria and fungus that could cause disease, especially in people with fragile immune systems like children. The most serious bacteria found was enteroccocus facaelis – indicating the presence of fecal matter.

Dr. Reynolds tells Inside Edition she wasn't surprised by the results. She had tested shopping carts as part of a university study on germs.

"Our study and your study seem to indicate that shopping carts are frequently contaminated."

On some carts, Dr. Reynolds found bodily fluids like blood, mucus and saliva. She says the shopping carts she tested were dirtier than public bathrooms.

"The fact is, bathrooms are frequently cleaned and disinfected, shopping carts are not," Dr. Reynolds told Inside Edition.

To demonstrate how the germs get from the cart to the shopper or their child, Inside Edition coated a cart with a fluorescent marker. Anyone touching that area would get a mark only visible under a black light. Then that cart was used on a shopping expedition with Margo Drucker, of New York City, and her four-year-old son, Jonah.

With Inside Edition cameras rolling, it didn't take long before Jonah was touching his face, areas around his mouth, forehead and eyes. His mother even playfully touched his face after she touched the handle.

Then Inside Edition brought Jonah and his mother back to the show’s studios and turned out all lights except for the black light. He had markings from the shopping cart all over his face, clothes and hands.

"Oh God, look at that. I'm shocked, this is very unnerving," Drucker said.

Inside Edition reports the solution that could prevent germs from being transferred from cart handles to a shopper or their child may be very simple -- sanitation wipes to clean the hot spots.

Gelson Markets of California is one of the few supermarket chains addressing the problem. General manager Tim Redman tells Inside Edition: "Sanitation is a very important part of what we want to offer our customers."

Inside Edition contacted ten of the largest supermarket chains in the country to find what they do to clean their carts. Two responded, saying they clean them several times a year. One supermarket pointed out that they have never heard of an instance of illness attributed to shopping carts.