500
Proper method for hand washing:
What is Turn on water.
Get a dimesize pump of soap.
Work up a lather on every part of your hand, front and back. Get in between the fingers, the wrists, and under the nails.
Wash under rings, but don't remove.
Wash for 20-30 seconds or sing Happy Birthday.
Rinse downward motion, avoiding splashing water off your hands.
Use a paper towel to dry your hands and then use another paper towel to turn off the water.