Your tongue is germ free only if it is pink. If your tongue is white, there is a thin film of bacteria on it.

1. Your tongue is NEVER germ free. It is impossible to "sterilize" the mouth or human skin

2. A healthy tongue is pink, moist, with small bumps and lines. White may indicate that the tongue needs cleaned (via toothbrush) or that a person has a 
fungal infection such as thrush. A tan/brown tongue is the same but with a smoker
    Some interesting facts about tongue :
  • Your tongue is a muscle. Made of skeletal muscle tissue, it is the strongest muscle in your entire body.
  • No tongue is the same. Like fingerprints, each person’s tongue is different.
  •  About half of the bacteria in your mouth rest on your tongue. If you brush your tongue regularly, you reduce the presence of these bacteria. 
  • The bacteria on your tongue are the number one culprit of bad breath.
  • The color of your tongue may reveal illness. For example, if your tongue appears to have a yellowish color, it may indicate fever or digestive problems.
  • Your tongue is surrounded by a coating of mucus membrane.
  • Taste buds on your tongue relay sensations of flavor to your brain. Taste buds detect sweet, sour, bitter, and salty flavors.
  • Although most taste buds exist on the tongue, ten percent of them are located on the inside of your cheeks and your palate.
  • Your tongue is the only muscle in your body that is not attached to other tissues on both ends.
  • Of all your body parts, your tongue heals the fastest.