Prior research has already concluded that two common bacteria that cause colds, ear infections, and strep throat don't often live for long outside the human body, but a new study finds that they can linger a lot longer than previously thought. Your best defense? Well-scrubbed hands.

University of Buffalo researchers in New York published a study December 27 in the journal Infection and Immunity that found that Streptococcus pneumoniae and Streptococcus pyogenes can live on surfaces such as toys, books, and cribs for weeks or even months.

"These findings should make us more cautious about bacteria in the environment since they change our ideas about how these particular bacteria are spread," says senior author Dr. Anders Hakansson. "This is the first paper to directly investigate that these bacteria can survive well on various surfaces, including hands, and potentially spread between individuals."

The researchers found that in a daycare center, four out of five stuffed toys tested positive for S. pneumonaie and several surfaces, such as cribs, tested positive for S. pyogenes, even after being cleaned. The testing was done just prior to the center opening in the morning so it had been many hours since the last human contact, the researchers said.

Hakansson and his co-authors became interested in the possibility that some bacteria might persist on surfaces when they published work last year showing that bacteria form biofilms when colonizing human tissues. They found that these sophisticated, highly structured biofilm communities are hardier than other forms of bacteria.

"Bacterial colonization doesn't, by itself, cause infection but it's a necessary first step if an infection is going to become established in a human host," Hakansson says. "Children, the elderly and others with compromised immune systems are especially vulnerable to these infections."

"In all of these cases, we found that these pathogens can survive for long periods outside a human host," says Hakansson. But, he says, the scientific literature maintains that you can only become infected by breathing in infected droplets expelled through coughing or sneezing by infected individuals.

"Commonly handled objects that are contaminated with these biofilm bacteria could act as reservoirs of bacteria for hours, weeks or months, spreading potential infections to individuals who come in contact with them," concludes Hakansson.

Still, ways to protect yourself and your children from getting sick is to practice good hand hygiene. Use warm water and soap and lather up for at least 20 seconds, advises the U.S. Centers for Disease Control and Prevention. Wash your hands frequently, especially after touching germy hotspots, such as shared toys, door handles, and faucets, and avoid touching your face as much as possible -- no rubbing your eyes or biting your nails either -- to avoid giving germs direct access to your body.

Still, you can't fend off all germs, so stay well hydrated, get adequate sleep, and reduce stress to help your immune system do its job.

Loading Slideshow...
  • Kitchen Drain

    The only thing in your home that houses more germs than the kitchen drain is <a href="" target="_hplink">your bathroom toilet</a>. And this is problematic since the kitchen drain is in close contact with many other kitchen items. A quick way to <a href="" target="_hplink">clean your kitchen drain</a> is to pour a little baking soda in it with warm water running.

  • Wash Cloth/Sponge

    You may think you're cleaning your plates and cups when in fact you could just be spreading bacteria all over them. A sponge or wash cloth can house <a href="" target="_hplink">134,630 bacteria/square inch</a>, so you may want to keep it clean. You can either zap the sponge in the microwave for a minute, run it in the dishwasher, or make sure all the food scraps are cleaned off and allow to dry completely.

  • Kitchen Faucet Handle

    When you need to wash your hands while making dinner, you have to use the faucet handle (with your dirty hands). The faucet handle essentially sees many hands before they've been washed, so don't forget to wipe it down.

  • Dish Towel

    A study written about on found that "7 percent of <a href="" target="_hplink">kitchen towels were contaminated with MRSA</a> (methicillin-resistant Staphylococcus aureus), the difficult-to-treat staph bacteria that can cause life-threatening skin infections." The best way to avoid germy kitchen towels is to wash them once to twice a week, and allow them to completely air dry.

  • Microwave Buttons

    When is the last time you wiped down your microwave buttons? For many of us, that answer would be close to never. But think about how many times dirty fingers are in contact those buttons. Next time you clean the inside of your microwave (which we sure hope you do), be sure to get the outside too.

  • Salt And Pepper Shaker

    In a recent study conducted by the <a href=" " target="_hplink">University of Virginia</a>, "researchers asked 30 adults who were beginning to show signs of a cold, to name 10 places they'd touched in their homes over the previous 18 hours. The researchers then tested those areas for cold viruses. The tests found viruses on 41 percent of the surfaces tested, and every one of the salt and pepper shakers tested were positive for cold viruses." To solve this, just remember to wipe down your shakers when you wipe down your kitchen table.

  • Kitchen Floors

    Make sure you mop your kitchen floors regularly, particularly the spot in front of the kitchen sink. You know how dirty that sink and everything that has to do with it can get, and the floor space right next to it is certainly not exempt.

  • Cutting Board

    Naturally, the cutting board is full of grooves and gouges from all the cutting that has occurred on it; those are great places for germs to hide. Be sure to thoroughly clean your cutting board with soap and hot water after each use. And it's a good idea to reserve one cutting board for meat and another for fruits and veggies.

  • Kitchen Counters

    Kitchen counters get loaded with a bunch of stuff. We throw our keys on them, grocery bags, purses, mail. The list goes on and on. And all these items that we put on the counter are loaded with germs from everywhere else they've been. Be sure to wipe down the counter regularly, and do it with a clean sponge.

  • Kitchen Sink

    Since the kitchen sink is where everything that's dirty goes to get cleaned, it makes sense that it's one of the dirtiest (and germ-iest) spots in your kitchen. The best way to solve this is to wipe down your sink regularly; treat it like you would a dirty dish.

  • WATCH: How To Avoid Cross Contamination

Also on HuffPost: