Trigalsky spatula turns black in flame - (Mar/01/2007 )

Hi
I have a very weird problem. When plating out bacteria after transformation I usually sterilize the trigalsky spatula in bunsen flame. Recently the spatula turns black in the flame, the longer it is exposed to the flame the more smut or whatever it is builds. As I do not have a gas pipe I use a kind of camping gas cartidge (also propan/butan mixture). Since I changed on a new cartrige (which is exactly the same kind I used before) this problem started.
I tried out glas and metal spatula / with and without dipping in ethanol before exposing to the flame, the spatula always turns black, and the bad thing is, I dont know if that can have any negative effect on my bacteria.
Has anybody experienced something similar before or has an idea why this is or how to stop it ?
I would be happy about any suggestions.

Even on camping gas cartridges is a trigger to open the "air vent" (or whetever it's called). So did you open it, meaning, do you work with a blue flame? Because if you have it closed and work with a red/yellow flame, then spatulas get sooty quite quickly.

Actually I don't believe the soot is harming your bacteria, since it should be mostly carbon. Anyway, it is better to avoid, I guess...

Hope that helps!!