Thanks for the responses jzmlt, gareth, benner, mike and black rose.
As for the soda I think the principle behind that is that the acid I think kills off the micro organisms.
I read about soda disinfection in the early 90's during the big earthquake in Baguio City Philippines. Baguio City was cut off from the rest of the country and was short of medical supplies, a story came up about a rescue a man or woman needed to have his/her leg amputated to be rescued. The rescuers have no choice they have to use a Jungle Bolo sterilized by soda to amputate the leg.