washing bacteria

[biology_06er]

Hi there,

What does it mean when it says "wash twice with PBS" regarding bacteria..does it mean after I spin down my bacteria, I pour off the supernatant and then add PBS and then spin again, pour off s/n add more PBS and spin...

OR DOES IT MEAN

just add PBS ensuring the pellet doesn't break up and then pipette out the PBS and then add more and take it out..?

cheers,
b_06er

[JackBean]

spin, resuspend in fresh PBS, spin, resuspend in fresh PBS, spin, dissolve