Color of TCBS media plate - (Feb/21/2006 )

hi folks,

just was wondering why the media plate of tcbs is green in colour when the indicator used is bromothymol blue which is blue at alk pH and yellow at acidic pH. when the medium is alkakine the colour of the plate green why ?

not my field, but what else is in there, sounds like you are adding something yellow to it too and yellow and blue make green!

TCBS is is used for the isolation and selective cultivation of vibrio's; the sucrose-positive strains grow to form yellow and the mixed indicator thymol blue-bromothymol blue changes its color to yellow, when acid is formed, even in this strongly alkaline medium.