The IRB-BART initially has an immediate reaction of a brown color at the bottom of the tube, then the brown color disappears leaving the solution yellow and no slime present. How should this be interpreted?

Document ID

Document ID TE1758

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
The IRB-BART initially has an immediate reaction of a brown color at the bottom of the tube, then the brown color disappears leaving the solution yellow and no slime present. How should this be interpreted?
Summary
IRB-BART initially has an immediate reaction to a brown color
Answer
This immediate reaction to a brown color at the bottom of the tube, followed by the brown color disappearing over the next few days is a phase one reaction which does not designate bacterial activity (see Standard Methods for BART Testing on www.dbi.ca). In this case the initial brown color in the base is triggered by the movement of ferric ions out of the base medium. Over time these ions disperse into the liquid medium as a yellow color.