In the same spirit as my post about antibacterial soap, it's become more evident to the health and medical community that being too clean is a bad thing. My dad always quoted his grandmother as saying "let them eat dirt" in reference to children, because she believed (as I do) that exposure to the vast majority of "germs" is a good thing. It makes for a strong immune system. So take a break from that obsessive cleaning!
Do exercise caution in the kitchen, however, in order to avoid the nasty food-borne illnesses. And the best way to avoid the cold and flu during the cold and flu season? Eat healthy, get some probiotics in your system, and if more sick people would stay home - that would help greatly!