pink agrobacterium

[Cayetana Schluter]

Hello,

 I think I remember somebody asking this question before, but I don't 
remember the answer so...

I'm having problems with my agrobacterium. 
Everything was fine for awhile, but now when I pellet it I get a pink 
pellet. I figured this must be some sort of contaminant so I've been 
super careful latly about keeping everything steril, but I still keep 
getting this pink pellet. Can anyone tell me what it is? Thanks

Cayetana