From the NMC Newsletter "Udder Topics", December 2005
The key to effective use of teat disinfectants as a mastitis control tool is consistent and complete teat coverage at every milking. The "white towel test" is an excellent easy way to provide immediate feedback to milkers about the effectiveness of their teat dipping. Immediately after the milker has dipped the teats, wrap a clean towel around base of the teat while blotting the teat dip from the entire teat. Open the towel and display the teat dip pattern. If the pattern shows incomplete coverage, training should be implemented to show the milkers the proper procedures which will result in the bottom two-thirds of the teat completely covered with disinfectant.