Would you believe that picking a cart to put your groceries in could produce the same bacteria as cleaning out a barn?

Well, that's what tests conducted by CTV and the Cantest laboratory found on one cart we tested - an overwhelming amount of bacteria you'd normally find on a horse.

"Sure it's surprising," said Chad Born, a spokesperson for Cantest. "We found rhodococcus species which is common in soil - we found a species that is common in horses."

The rhodococcus bacteria was found on a sponge that was wiped on the handle of a supermarket grocery cart.

That was the same cart that produced more bacteria than three of the public toilets also tested by CTV.

It was all part of an investigation into the dirt that you can't see - and finding out a little more than most of us wanted to know about what lurks on the surfaces we touch every day.

Barbara Bulteel and her friend Marcina Gamiet were two of several people who agreed to let CTV test the handles of their grocery carts.

Bulteel said she's germ-conscious, but only to a point.

"I think about it," she said. "Especially in washrooms. But in carts I don't really think about it."

Her cart came in with only 80 bacteria on it - less than a quarter of the bacteria we found on a public library toilet seat.

But on Lois Neely's cart, we found 1000 bacteria - more than twice found on the toilet seat. And on Rob Schmidt's cart, we found 9000 bacteria.

According to Vancouver Coastal Health's medical health officer, Dr. John Carsley, a healthy person won't get sick from rhodococcus, even at that level.

But someone feeling tired, with a cut in their skin, or with a compromised immune system might find themselves vulnerable to a bacteria that wouldn't normally cause trouble.

"Even in healthy people, how you respond to germs varies," said Carsley. Having a proper diet and sleep patterns can help people fight off the effects of unwanted germs, he said.

While the amounts of bacteria CTV found on the shopping carts surprised microbiologists, none of the species of bacteria CTV tested are considered dangerous.

Among them bacteria usually found in a person's ear, and a germ that creates odor in sweat found on a restaurant PIN pad.

"If you didn't find any germs in the environment you'd be saying 'what's going on here, who's been spraying what terrible chemical around?' We need germs to live," said Dr. Carsley.

With a report from CTV British Columbia's Sarah Galashan and Jon Woodward

Tomorrow: Some bacteria can be deadly. CTV explores what can happen if you pick up the wrong one.