For day to day uses, I usually just wash the blade with a little bit of dish soap and water. I generally only clean it after using it to cut food, or if I had used it to open something nasty. I have used the same knife to open the foil on the top of an STP bottle or Prestone anti-freeze, then wash it with soap and water. Then using it to cut food at a later date. We injest so much toxics in the air we breath every day, a few ppm that escapes the washing will make no difference, unless you are talking really nasty biohazards. Have you ever drove at 5 mph in rush hour traffic behind a diesel truck whose maintenance schedule is suspect?

In a true emergency in the wild, I suspect you will be lucky to find a sandbank to stab the blade in a few times to clean it between uses when the occaisional food finds its way to your cooking pot.

If we die from cancer, it will be from years of accumulated gunk in our systems from what we breath, drink, and eat, with some sprinkling of occupational hazard thrown in on the side.

Use your knife. It is a wonderful tool. They do not need to be specialized for utility or food. Just clean them between uses.