It's time to check in with one of our favorite microbiologist, germ experts, Dr. Charles Gerba. The topic today is how our clean clothes can still be loaded with bacteria when they come out of the washer. We read about this on ABCNews.com.It seems our washing machines are teeming with bacteria that can find its way onto our clothes, and then onto us. The biggest culprit? Undergarments. To be specific, Dr. Gerba says there's about a tenth of a gram of human waste matter in the average pair of underwear. That carries all kinds of germs, including the hepatitis A virus, salmonella, norovirus - which is the bacteria people get on cruise ships that leads to nausea and vomiting - and E. coli. In fact, a load of underwear can leave about a 100-million E. coli in the water, and those germs can be transferred to the next load of clothes! Another source of washing machine germs is kids' clothes. Their clothes - and especially their underwear - carry a lot of germs. Also, your towels can harbor staph bacteria from your skin.So what's the fix? Contrary to popular belief, your detergent can't get rid of that mess alone. You need to use either bleach or very hot water - between 140 and 150 degrees - to actually kill the germs. If you can't wash those clothes in hot water or you can't use bleach, consider using something like Clorox 2, which has peroxide, in the warmest water setting allowed for your clothes. Make sure you wash your hands after handling wet clothes to avoid spreading germs to other parts of your home. Another option is to periodically clean your washing machine with bleach and water. Just run the washer without clothes and let it go through its normal cycle. If you really want germ-free laundry, consider hanging your clothes outside in the sun. The ultraviolet radiation is just as effective as bleach for killing bacteria.