Re: ultraviolet light (edited)

 Do you think ultraviolet light is a good way to disinfect water or countertops? What about food?

This wand is inexpensive.

www.colonialmedical.com/product.php

Yes, UV is very effective in killing pathogens.  These germicidal lamps actually generate ozone as well.  I have an ozone generating bulb system that I have loaned to friends with water damage to fry the mold.  Be careful with your eyes though because it will do the same to your eyes really quick.  I did this by accident once.  It only took a few seconds and my eyeballs were red as could be and felt like they were full of sand for weeks.