Thus organisms capable of lactose fermentation such as Escherichia coli, form bright pinky-red colonies (plate pictured on the left here). MacConkey agar is commonly used to differentiate between the ...

But when the students go home, Grosser gets out her agar plates ... blue colonies. “While this is not my neatest work or most complex design, I love the way the colors turned out,” said Grosser. To ...