After that new car smell goes away, you may want to spend a few minutes keeping your car's interior clean, especially knobs and buttons you push all the time, according to a recent University of Arizona study.

Scientists examined in the interiors of 100 cars driven in 11 states from California to Florida for signs of mold and bacteria, and discovered some interesting differences. Singles and men maintained the cleanest cars and Arizona residents enjoyed the least amount of bacteria in their vehicles.

As you'd probably expect, the cars of married folks contained the most germs, likely due to kids and extra car seats. Also, the Florida weather -- humidity along with high temperatures -- pushed Tampa to the top of the list in terms of bacteria, with 10 times the number of germs found in cars driven by Tucson residents. Conversely, cars tested in my native Chicago had 15 times the amount of mold than in Tampa.

The two places where bacteria collects the most in your car -- Spots where food has been spilled and on your dashboard, the warmest spot in your car -- likely explain why Arizona researchers recommend cleaning stains and areas your bodies touch the most once a week.

Protect your health and that of your family by washing your hands, ideally with plain soap and water, while avoiding antibacterial soaps.