Re: does 'spit' in a brass instrument contain bacteria diff. than in mouth?

I would expect it to be pretty similar. After all, the spit in the 
instrument is coming right from your mouth. It may depend upon when you 
take a sample though. Many bacteria are sensitive to metals so they might 
die off quickly in the instrument whereas others might grow better. So 
after a while the flora might change. But if you sample the "spit" fresh 
after playing, I think it would be much the same.

How would you test this? Take a sample of saliva from your mouth and a 
sample of the spit from your intrument. Then you would need to run some 
microbiological tests on them. The simplest would be just to plate it out 
on some solid growth media (petri dishes) and see if the types of 
bacterial colonies that grow look similar or not. If you wanted to get 
fancy you could test a number of these colonies and do a profile - 
determine what the bacteria actually are. But that requires a bit of work, 
especially for a large number of different bacteria.

I think you would get a pretty good answer just by plating them out.