what is 0.5 x TSB? - (Apr/30/2010 )

What is 0.5 x TSB? my guess is a diluted form of TSB. I've also seen methods call for 1 x TSB.

Other question; if I purchase TSB media already made up and I need to add something (like powdered saponin for neutralization), can I re-autoclave it? I'm just thinking of damaging the nutrients if autoclaved too many times. Or, maybe it's better to just dissolve the powder in water and sterile-filtrate it...thoughts?

0.5 means usually only half the amount of nutrients (so diluted 1:2).

I would filter-sterilise the additives. Otherwise sugar burns or metals can form precipitates etc.