|MadSci Network: Microbiology|
Warm water verses cold water certainly encourages people to wash hands/dishes. The most important factor in washing hands/dishes is the removal of organic matter ( in the case of dishes food and in the case of hands....soil or fecal matter). The temperature of water in hand washing is not very important except in helping to dissolve oils etc. The recommended temperature is 32-43oC (90-110oF) for hands and 30 seconds. However, washing dishes in hot water (Temperatures above 60oC (140oF)) will certainly kill most bacteria. This is too hot for hand washing. Tell your wife to let you use whichever temperature is most comfortable. You will get them just as clean and it will be a much more pleasant task.
Try the links in the MadSci Library for more information on Microbiology.