Debra Farber, a New Jersey mother, uses her SUV for way more than just getting from point A to point B.
Sometimes, her car is an office and sometimes, a closet. With two kids under three years of age, it's often a dining room.
Little does Farber know that her car could be a breeding ground for bacteria.
Like so many American moms, Farber, who works full time in pharmaceutical sales, lives in her car and it shows.
"Crumbs, raisins, bagels, anything the dog can't eat, it's in the car," Farber said. "Half the time, I'm like jumping in and out of the car. I don't have time to clean it. I try to get to the car wash as often as I can but it doesn't always happen."
Compare that to her husband Steven Farber's brand new BMW, which the kids have only been allowed to ride in a couple of times.
"His car is like the sanitarium," she said. "He doesn't even let me drive the car."
Farber admits she would never let her house get this way.
ABC News asked germ expert Dr. Chuck Gerba, a University of Arizona microbiologist, to swab every inch of Farber's SUV and her husband's BMW to let them know, for better or worse, what's growing in there.
"We found that cars are the moldiest of all forms of transportation," Gerba said.
He added that most people don't realize their cars are perfect breeding grounds for germs.
"In cars, germs seem to tend to build up because people aren't really cleaning or disinfecting these areas," he said. "Our germs are traveling with us and everybody that travels in that car carries their germs and leaves them in your car."
Gerba took the samples back to his lab while Debra Farber waited and worried.
"It's definitely making me nervous. I mean, obviously, I wouldn't want to expose the kids to any harm ... They both have colds now," she said. "I'm sure you'll find plenty of germs in the car."
Unfortunately, Farber was right. Gerba found millions of bacteria on the door handles, seat and floor of the SUV, compared to just a few hundred in Steven Farber's new BMW. Gerba even found MRSA, a staph bacteria that can cause skin infections.
"The germiest areas in your car are your dashboard, your change holder and where you keep your coffee, actually," Gerba said. "The reason is ... because the air flows ... over your dashboard and so, the bacteria tend to build up on that surface."
On the car seat, Gerba found hundreds of thousands of bacteria from the sample he took, plus mold all over a child safety seat.
The SUV's radio dials, however, were quite clean; Debra Farber is the only person who touches them.
As for the rest of the car, Gerba says Farber should consider wiping down some parts with a disinfectant once a week.